by KMom
Copyright © 1999-2001 KMom@Vireday.Com. All rights reserved.
DISCLAIMER: The information on this website is not intended and should not be construed as medical advice. Consult your health provider. This particular web section on gestational diabetes is designed to present more than one view of a controversial subject, pro and con. It should be re-emphasized that nothing herein should be considered medical advice.
CONTENTS
Can Gestational Diabetes Be Prevented?
If you are at increased risk for gestational diabetes, is there anything you can do to help prevent its occurrence? The truth is that no one knows for sure. Few studies have focused on preventing gd through proactive health measures, and few physicians are trained enough in nutrition issues to use it proactively, preferring to deal with it once it appears instead. Traditionally, physicians' emphasis is on INTERVENTION instead of PREVENTION, and this is often particularly true in obstetrics. Thus most women, even those at most risk for gd, are not given much guidance about possibly ways to lower their risk. Most OBs prefer to simply test more often instead, hoping to catch it early.
There is some mixed evidence that careful attention to nutrition may help prevent at least some cases of Pregnancy-Induced Hypertension; could this also help with gestational diabetes? Many midwives report anecdotally that they prevent or reduce the number and severity of gd cases through the use of proactive nutrition and exercise. Since this is 'only' anecdotal and not documented by double-blind, randomized studies, many physicians tend to dismiss the efficacy of this approach. However, it may be worth exploring further, especially if you have a number of risk factors for gd.
It is important to re-emphasize that this has not been studied adequately to determine scientifically the value of this approach. In the absence of such research, however, it makes sense to take the anecdotal reports seriously, as limited as that can be, instead of just waiting for the gd to happen and then treating it. Taking a very proactive attitude towards healthy habits during pregnancy (good diet and exercise, etc.) can only help and not hurt, as long as the approach used is reasonable and safe. What have you got to lose, except a possible diagnosis of gd and all the trouble that can buy?
Remember, though, that not all cases of gd can be prevented, no matter how careful you are (though you may minimize your case), and that people who do not have the genes for gd won't get it, no matter how poor their habits are. Family and genetic history are a very strong factor in developing gd, but it is also known that lifestyle and other factors also affect development of gd. The best idea is to change what you can change, be as proactive as possible, and not worry about the rest. Be very proactive in health habits (so that if gd occurs, you can minimize its effect on you and on the baby), and if you are very high-risk for gd, consider more testing (so that if the gd does show up, you can catch it early). But in the meantime, focus your energy on being as HEALTHY as you possibly can, and don't stress over the rest.
If ever there is a time for extremely careful attention to health habits, it is during pregnancy. Do as much as you can to ensure a healthy pregnancy. Your baby is depending on you!
Kmom's story: In my first pregnancy, I got a mild case of gd at the usual time (7 months). Looking back with the knowledge acquired from several years of researching gestational diabetes, I see that I might have minimized my chances of gd if my doctors had only been more proactive about counseling me on how to avoid some of the risks, and if I had only taken more responsibility for researching as well. It wasn't that I was eating horribly or being really unhealthy. Although not perfect, I was pretty normal in my approach. However, I have since learned of some mistakes that I made that are very common, and ways that I could have perhaps decreased my chances had I only known them. There is no guarantee that I could have prevented it, of course---no one has a crystal ball to see that kind of alternative future. And certainly there were HUGE life stresses in that pregnancy that were totally unavoidable that could have caused/added to the gd.
However, I think that there is a strong case for the fact that proactive action could have helped, since in BOTH my second and third pregnancies I acted extremely proactively before I even conceived again, and was able to avoid the gd those times, even though I was over 35. Many factors could contribute to avoiding the gd, and one case does not a conclusion make, but it's certainly compelling anecdotally. Since I am an older mom, I could very well have my gd recur in the future, but you can bet I'll be as proactive as heck to minimize the risk as much as I can!
Who is most at risk for gestational diabetes? This subject is covered in much more detail in another websection (see GD: Who Is At Risk?), but here is a brief summary to enable you to identify your own risks. The more risk factors you have, the more proactive you should be, although it should be noted a number of cases of gd occur in women without risk factors. And of course, larger women are at a somewhat increased risk of gd, but do remember that even so, most larger women do not actually get gd.
The main risk factors include a family history of diabetes (especially in a first-degree relative, like a mother or sister), maternal age (over 30, and especially over 35), ethnicity (especially Native American or Hispanic), obesity, PolyCystic Ovarian Syndrome, history of multiple unexplained pregnancy losses, a previous birth in which the baby weighed more than 9 lbs., your own birth weight greater than 9 lbs., possibly high parity (4-5 kids or more), a previous pregnancy with gd, central fat distribution (an 'apple' shape), significant weight gain in early adulthood or between pregnancies, smoking, and perhaps excessive weight gained during the pregnancy. Other risks factors may include hypertension, multiple pregnancies, use of steroids or certain other medications, a tendency towards hypoglycemia (low blood sugar reactions), and a history of chronic skin/genital/urinary tract infections.
Although ALL women should be proactive, the women who should probably be MOST proactive might include women with PCOS (some studies have found that ~40% of women with PCOS get gd). Native American or Hispanic women also have particularly high gd rates, and heavy women, older women, and women with a strong family history of diabetes are probably also more at risk for getting gd. However, please note that no one can predict with 100% accuracy who will get gd, even when there are multiple risk factors or no risk factors at all! According to some studies, nearly half the women who end up getting gd have no identifiable risk factors at all, and there are many women who have multiple risk factors for gd but never end up getting it anyhow. So you never know---it's difficult to predict. However, it is only sensible to be as proactive as possible, since severe gd can cause definite risks to the baby.
What's the point of being so proactive about gd prevention? Is it really that bad or harmful? What would it mean to you and your baby if you were diagnosed? Can it really be avoided at all?
If you did develop gd, you can rest assured that with appropriate treatment and effort, you CAN have a healthy baby. It doesn't have to be a terrible, burdensome ordeal, and many mothers (including Kmom) have made it through gd pregnancies just fine. However, there is potential harm if you do have truly high blood sugars, as this can tend to make a baby grow bigger (or bigger in selected areas that make birth harder), or in more severe cases, tend to have more metabolic problems after birth (low blood sugar, jaundice, low calcium levels, etc.). You want to give your baby the best possible shot at health, so it makes sense to be as proactive as possible about being careful about blood sugars ahead of time, particularly if you are in one of the groups at higher risk for gd.
It's also true that in the current obstetric mentality, being diagnosed with gd subjects you to a GREAT deal of intervention, and the value of much of that intervention is debatable in less severe cases. Women diagnosed with gd are usually given a special sensible food plan to follow (which is good and appropriate, and which Kmom is all for), but sometimes they are also given low-calorie plans that are restrictive and questionable for pregnancy, and which could possibly be more harmful than beneficial. GD moms also have to do periodic 'fingerprick' tests (usually several times daily) to test their blood sugar, which although tolerable, are annoying and inconvenient at times. Although protocols vary tremendously from one provider to the next, many gd moms are also subject to a great deal of extra prenatal testing in the last weeks of pregnancy, which adds a lot of expense and stress. Some gd moms may truly need to be put on daily insulin injections, but the current push among some doctors is to place even marginal women (especially obese ones) on 'prophylactic' insulin, which may or may not be a good idea, and certainly adds to the stress because of the extra care routines involved.
Finally, having the gd 'label' tends to make doctors extremely interventive about delivery practices. Several recent studies have shown that just the mere label of gd increases the rate of c-sections significantly, even when the potential cause of c-sections has been successfully treated. Doctors tend to use a VERY high rate of labor induction in gd cases, and that makes for longer, harder labors and births in general. Furthermore, labor induction is strongly associated with c-sections in first-time mothers in particular, which may account for some of the high rate of c-sections in gd moms. Also, doctors tend to have very strict protocols regarding baby size in gd, and are VERY quick to do an elective c-section if they even suspect that your baby might be big. Although you can do it, it's not easy to take care of a newborn AND recover from major abdominal surgery at the same time, and c-sections tend to lessen the rate of breastfeeding and can also impede bonding. Although the complication rate with c-sections is much lower than it used to be, and most women who have c-sections do fine, statistically it IS a riskier way of giving birth, and although rare, complications CAN occur. A c-section also places any future pregnancies at somewhat increased risk of problems, so it is not to be taken lightly.
So although you could certainly deal with gd well enough should you be legitimately diagnosed with it, having that gd label certainly does increase your chances for a lot of interventions and for a c-section. If you can act now to prevent that label from needing to be applied to you, you have a better chance at avoiding many of these problems. As the saying goes, "an ounce of prevention is worth a pound of cure."
Some women who appear to have a very high risk of gd may think to themselves, "Why bother? Can gd really be prevented in my case?" The answer is that we do not know, but that probably at least some cases CAN be prevented, and others may be minimized. Kmom's case is a good example--despite being theoretically very high-risk for developing gd, she managed to avoid it in 2 of her 3 pregnancies. She had it in her first pregnancy by not being as proactive as she could have been, but was able to prevent it subsequently by being strongly proactive instead, despite the tremendous odds that it would recur (and more severely) as she aged. Being proactive won't work for all women; some women ARE still going to get gd. But perhaps being proactive can prevent them from getting it as severely, and that may well help protect the baby from the more rare and scary risks of gd. Certainly Kmom has heard from a number of women anecdotally that they were able to prevent a gd recurrence by being more proactive, and many midwives swear that they are lowering the number of cases of gd they see by advising clients on being more proactive.
Really, it's just plain COMMON SENSE to be as careful and proactive as possible. That means some sacrifices, mind; it means giving up all or nearly all sweets in pregnancy, it means minimizing or cutting out junk food if that's one of your vices, it means getting daily exercise, it means paying closer attention to what you eat and especially how you time that eating, it means lowering your stress levels as much as possible, and it means committing time and energy to researching and understanding the complex issues of gd and proactive care for childbirth in general. But isn't your baby's health worth that?
Pre-Conception Care and Testing
If you are not yet pregnant, you should plan on having your blood glucose tested BEFORE trying to conceive, so that you can clearly establish that your blood sugar is normal beforehand. If your blood sugar is not normal before trying to conceive, it is vitally important to get it under control before trying to get pregnant, since high blood sugar at conception and in the first trimester is strongly associated with multiple birth defects and miscarriage/stillbirth. Research has shown very clearly that a preconception care program and tight blood sugar control in women with previously high blood sugar strongly improves pregnancy outcome. Kmom cannot emphasize enough the importance of establishing normal readings before conception if possible, and of achieving tight blood sugar control before conception in women with abnormal readings. There is no controversy at all on this question!
Types of Blood Sugar Testing Available Pre-Conception
There are a number of blood sugar tests available, and which one is chosen depends on the doctor's preference. The most commonly ordered tests include the fasting blood sugar test, the postprandial blood sugar test, the glucose tolerance test, the random blood glucose test, the glycosylated hemoglobin test, and the fructosamine test. Each of these has advantages and disadvantages. The most commonly used test is the fasting blood glucose, but probably the best test to use is the glycosylated hemoglobin test; if your doctor is amenable, ask for both! However, whatever test is used, the results can at least give you an idea of your basic blood glucose levels. The following is a basic summary of the various tests and the context of those results; for more thorough information, consult the sections on GD: Testing Issues and GD: The Numbers Game.
As noted, the most commonly used test is the fasting draw, probably because it is one of the cheapest and easiest. This involves an overnight fast and a blood draw. Most labs require a non-pregnant fast of approximately 12 hours, no more and no less (doctors are not always very strict about this but should be; variations in duration can alter test results). It is important to have a good snack with protein (but no sugar etc.) shortly before starting the 12 hour fast, but only water thereafter. Not even gum, coffee, or mints are permitted, nor is smoking, since these can all raise the results. If you are pregnant, the fasting does not need (and probably shouldn't be) a full 12 hours; about 9 to 10 hours seems optimal for most women.
You should also follow your normal routine for this test; if you are a morning person, have the test done first thing in the morning when you would normally eat, but if you are a late-night person, getting up early for a test at an abnormal time of day for you is probably not a good idea either. Whenever you schedule your test, just time your fast to last for the appropriate interval. Do not go for a walk or do a lot of activity before the test; your body stores sugar (glycogen) in your liver and if your body feels 'starved' or gets too low from fasting, it will draw on these glycogen reserves, thus artificially raising your numbers. At about 12 hours, you should have your blood drawn (from your arm) and the results sent to a LAB for testing. (Portable monitors can give a general idea of results, but they are NOT accurate enough for diagnosis and should always be backed up by lab results).
Testing Guidelines:
In a NON-PREGNANT person, normal fasting results are <110 mg/dl, preferably less than 100 mg/dl, with the most optimal results being below 90-95 mg/dl. If your fasting results are <90 mg/dl, you can probably go ahead and try to conceive. If your fastings are in the low 90s, it's probably fine too since fastings tend to drop somewhat in pregnancy, but you might want to discuss the situation with your doctor just to be cautious (most will not be very concerned). If your fastings are in the upper 90s, discuss getting pregnant with your doctor, and you might want to have a glycosylated hemoglobin test done to be sure that most of your other readings are okay. If your fastings are above 100, be sure to consult your doctor before conceiving. Technically non-pregnant levels between 100-110 are still normal, but in pregnancy they prefer fastings to be <105 for sure and generally lower than that. You might also want to have any borderline results re-done, just to be sure there is no error.
Results between 110-125 mg/dl are considered abnormal but not yet diabetic; this level is called 'Impaired Glucose Tolerance' and may or may not lead to diabetes in the future. However, IGT levels are too high for pregnancy, where the desired fasting results are <105 mg/dl and preferably lower than that. Before trying to conceive, consult an OB about your situation, re-test to rule out error, and try to also have a glycosylated hemoglobin test done to see whether the rest of your blood sugars are tending to run high.
Results >125 mg/dl are considered diagnostic of diabetes (again, get a second test to confirm it). If your readings are abnormal or borderline, do not try to conceive yet! Consult your doctor first. It is critically important to have excellent blood sugar levels before trying to conceive a child.
It is important to note that the weakness of a fasting test is that it only measures how your blood sugar does after a period of not eating; you can have normal fasting levels and abnormal numbers after a meal. So having normal fasting results is only one step in establishing normal blood sugar; you need either a postprandial blood glucose test or a glycosylated hemoglobin test to further confirm that all is well.
Fasting tests are also simply a one-time snapshot of your blood glucose (bG) levels on THAT day, and you can get either higher or lower numbers than normal due to other circumstances such as stress, illness, amount of time since eating, etc. If you are at low risk for gd, it may be enough to simply order a fasting test before pregnancy. If you are at high risk for gd, you should probably request a fasting test AND one of the other tests.
Post-Prandial Blood Sugar Test
As noted, the fasting test measures only how your blood sugar does after a period of not eating, whereas some people instead have trouble clearing the glucose from their systems after eating. It is possible to test normal on a fasting test and yet still have high blood sugar after meals, which can also endanger a baby. Therefore, another test that doctors sometimes use is the postprandial blood glucose test. This involves eating a meal and then drawing blood exactly one or two hours later to check to see if your system is adequately clearing the glucose from your system.
Testing Guidelines:
Unlike fasting blood sugars (which tend to decrease during pregnancy), post-prandial measurements tend to increase in pregnancy because the hormones tend to slow digestion of foods in order to make more glucose energy available to use for the baby. Therefore if your numbers are above these guidelines, be sure to consult your doctor before trying to conceive; chances are your results will increase, especially towards the end of pregnancy.
The weakness of this test is that not all meals are equal, and it is difficult to standardize results for varying meals. However, if the meal is of average size and not excessively carb-laden, a <120 mg/dl cutoff is usually fine to use. Oftentimes, a fasting blood glucose test is used in combination with a postprandial test. This tests both the person's blood sugar levels in long periods between meals and their response to a carbohydrate load. Of course, as with the fasting test, another weakness of this test is that it is a one-time snapshot of a person's response on that day; illness or excess stress, etc. can sometimes cause an abnormal result.
Because of the desire for standardized test materials, some providers use a Glucose Tolerance Test (GTT). This is less common since it is more costly and requires more time, so (outside pregnancy) it is usually only used if the doctor suspects a pre-existing problem. In this test, a fasting blood sugar test is usually given, then a special drink of 'glucola' (sugar water that tastes like orange, cola, or lemon-lime soda pop) is given. After a set amount of time, another blood sample is taken to measure blood sugar levels. In the test for non-pregnant people, the test lasts for two hours and the glucose load is 75g (in pregnancy the test is longer and the glucose load heavier). In the past the GTT was the recommended method for diagnosing diabetes, but the standards have been changed recently to rely more on fasting numbers instead of the GTT, although some doctors still use both. Consult your doctor.
Testing Guidelines (also see the fasting results above):
These are the guidelines that have existed in the past. Because standards are changing, consult your provider as to what constitutes 'normal' on the GTT.
Another test that is sometimes done by a few providers is the random blood glucose test. In this, a blood draw is taken at any time of day, regardless of fasting or not, but should not be done immediately after meals. It is important to remember that this test cannot be done within two to three hours of a meal or the results will be higher due to eating.
Testing Guidelines:
The advantage of this test is that you don't have to fast, it is quick and easy to do, and it checks to see if the blood glucose has adequately cleared your system between meals (in diabetics it often remains elevated). The disadvantage of this test is that, like the other tests, it can be easily influenced by stress, illness, caffeine, smoking, etc., and that it does not test the normalcy of your bG after meals or fasting.
Probably the best test to get is the glycosylated hemoglobin test (abbreviated as HbA1c, HA1c, or glycohemoglobin test). This test is the best OVERALL measure of blood sugar control. Although it's complex, what the test more or less does is measure your average blood sugar over the space of about 2 months or so, and therefore gives a clearer long-term picture of your bG status. It will reflect your OVERALL bG status fasting, just after meals, and between meals. It is probably the best test for establishing normal bG levels, but it is not always used because it can be more expensive and not all insurances will cover it. However, this is the test to lobby for if possible.
Testing Guidelines (norms vary from lab to lab):
It is important to understand that normal HbA1c test results vary from lab to lab, but usually fall between 4-6%. It is thought by some diabetes experts that <5% is most optimal and least associated with birth defects and problems, but many women with results in the low 5% range also have normal pregnancies. It is important in the HbA1c test to ask for your specific lab's norms, since different labs can differ a bit in their results. Your provider can interpret your results for you. It is also important to point out that the HbA1c test CANNOT be used to diagnose gd in pregnancy; it does not detect blood sugar changes quickly enough for utility in pregnancy.
Another test that is a slight variation of the Glycosylated Hemoglobin Test is the Fructosamine test. Basically, this test measures your overall blood sugar control as well, but for a shorter period of time. Instead of measuring your 'average' blood glucose levels over 2-3 months, it measures it for a period of about 30 days. Consult your provider for norms and how to interpret your results.
Other tests that may be appropriate for a few women to consider are the various insulin tests. These measure how much insulin resistance your body has (i.e., how well your body utilizes its insulin). These are particularly important tests for women with PolyCystic Ovarian Syndrome (PCOS), which is characterized by very significant insulin resistance. Because of this, PCOS moms have some of the highest rates of gd around.
In these women (and sometimes in others), excess amounts of insulin may be present in the body despite perfectly normal bG levels, so a blood sugar test doesn't really show the problem. Some studies have found that abnormal insulin test results tend to indicate a predisposition to insulin resistance and/or gestational diabetes, so women who have abnormal results on insulin tests should probably be tested for gd more often in pregnancy and be particularly proactive in diet and exercise. However, insulin tests are by no means universal even among those who treat PCOS patients regularly, and may be hard to get covered by an insurance company. It is certainly not a required test and only time will tell its utility, but it is one more in an arsenal of tests to consider if you are at special risk because of problems like PCOS.
There are different types of insulin tests. A fasting insulin test measures how much insulin is in your body when fasting. Another test compares how much insulin you secrete vs. how much blood glucose you have, and it is the PROPORTION of these two numbers that indicates a potential problem. These tests are are a fast-developing area of endocrinology so be sure to consult your provider for the latest information about which tests to take and how to interpret them.
Summary of Possible Blood Sugar Tests
If possible, get the HbA1c test since it represents a more accurate overall and long-term picture, but the fasting test or any of the other tests can be used. Whatever test is used, ask for your test results and the diagnostic cutoffs used, and be sure to get a copy of these for yourself, even if all is well. A few OBs and midwives may ask you to prove that you had normal blood sugars before beginning pregnancy. In addition, it may also help you establish your health status down the line if you have documentation that at "x" age you had normal blood sugar. Therefore, get a copy of your test results and keep them permanently in your files.
It is important to point out that blood sugar testing is not error-proof, and some authorities strongly question the validity and reliability of its results (especially in pregnancy). Test results can be strongly affected by things such as stress and illness, and results are not always reliably reproducible. In other words, your test results should come back more or less the same if you repeat the test a few days or weeks later, but sometimes this doesn't happen. That's why it's always important for you to repeat the tests if your results turn up abnormal. Chances are the test was accurate, but it's important to rule out the possibility of a lab error or a randomly errant result. The point is to know what your blood sugar levels are like on a reliable regular basis. Always retest if you get any abnormal results.
If your blood sugar is normal and all other factors (such as blood pressure, etc.) are fine too, then you can go ahead with your plans to conceive. It is still wise, though, to begin a gd food plan and exercise regularly before becoming pregnant, as this may help prevent some cases from developing during pregnancy, or at least keep them from being more severe in other cases. Since gd does occur more often in some groups of women, it is best to be very proactive about preventing/treating it, especially if you fall into higher-risk categories such as women with PCOS, heavy women, Hispanic or Native American women, or women with a family history of diabetes.
Once You are Pregnant: Testing
If you are already pregnant and are at strong risk of gd, it may be appropriate to have your blood sugar tested in both the first and second trimester. Normally, most women have their blood sugar tested between 24-28 weeks, when the placental hormones become strong enough to interfere with insulin sensitivity. However, women with very strong risk factors are often tested earlier in the pregnancy as well. Catching a more severe case of early-onset gd can help prevent a lot of problems later on for baby; it can be to your advantage to discover gd early, if it exists. Early testing for the first trimester, though not mandatory, is probably a sensible precaution for women at very strong risk of gd. For women not at as much risk, its value is much more debatable.
How much testing and how aggressive the testing cutoffs should be is a matter of strong controversy. Your doctor should not be testing you for gd every single month simply because of your size, for example, but once in the first trimester and once in the second trimester may be appropriate. If your results are borderline in any way or there are other medical indications such as PCOS or a strong family history of diabetes, a test in between trimesters, again later at 32 weeks, or a specialized HbA1c test at any time might be appropriate in a few cases. However, one test in the second trimester is sufficient for most women; adding a test in the first trimester or early in the second trimester may be appropriate for women at stronger risk for gd. It is not, however, mandatory, and some providers feel it introduces more risk than benefit. Another test in the third trimester is only necessary for those at the most severe risk of gd.
Another question to ask is what set of cutoffs your provider uses to determine 'gd'. Although severe cases of gd almost certainly benefit from treatment, there are tradeoffs in diagnosing borderline levels, and some doctors have become extremely aggressive in diagnosing 'gd' at lower and lower levels. At what point the risks of gd treatment are outweighed by the risks of not treating is a matter of HUGE debate among health care professionals. So it is important to know just how aggressively your doctor screens for gd and why, what diagnostic cutoffs are used and why, and how aggressively he/she uses resulting interventions (see other GD web sections for more details on this very important debate).
If you feel that your provider is deluging you with unnecessary testing or feels that you WILL get gd simply because of your size (or other risk factors), you may want to strongly consider switching providers. It's important to remember, for example, that the vast majority of large women do NOT get gd, and a doctor's attitude that you are high-risk disaster just waiting to happen is extremely harmful. You need a size-friendly provider instead, one that will recognize the risk factors and test appropriately for them, but who will not assign added intervention, over-monitoring, or negativity where there is no proven need. This is very important! (See the web section on Finding a Size-Friendly Provider.) You might want to consider midwives, who generally are more open to treating the risk for gd proactively without over-reacting, no matter what your particular risk factors are.
For more information about gd testing during pregnancy (since testing protocols and diagnostic levels often change for pregnancy), see the websection on GD: Testing.
Once You are Pregnant: Exercise
One of the MOST important things you can do to possibly prevent gd from occurring is to exercise regularly. A recent study (Dye, 1997) found that this is particularly important for large women. In this study, regular exercise did not affect the rate of gd among women of average size, but among larger middle-class women, regular exercise cut the occurrence of gd in HALF. This is a very important finding!
Little research other than this study has been done to investigate the effects of exercise on the prevention of gd. Research does show that it can help many women significantly after they are diagnosed with gd; some women were able to avoid needing insulin simply by increasing their exercise levels after diagnosis (see references and websection on GD and Exercise). Furthermore, research with regular diabetic subjects shows that regular exercise improves blood glucose control, blood lipids, and sometimes blood pressure---sometimes modestly, and sometimes dramatically. It seems logical to assume that it might help prevent some cases of gd.
However, exercise must be REGULAR in order to improve blood sugar levels and insulin response. Horton (1991) found that "acute exercise in untrained subjects is also associated with increased insulin sensitivity and glucose metabolism that persists for several hours after the exercise." In other words, the exercise session didn't merely improve blood sugar after the last meal, it also improved glucose metabolism for the next 12-14 hours. If exercise is regularly done (i.e. daily), then even more improvement often occurs. However, "the increase in insulin sensitivity and responsiveness associated with physical conditioning is rapidly lost when [regular] exercise is discontinued." Although results vary from study to study, exercise is probably most effective at improving glucose metabolism if it is done daily, or at least every other day. Going more than 2 days without exercise loses its benefits.
Although there is no absolute proof, Horton concludes that "based on current knowledge, it seems rational to consider regular physical exercise as a potential approach to the prevention and treatment of GDM. The large body of literature demonstrating that physical training is associated with lower plasma insulin concentrations and increased sensitivity to insulin in skeletal muscle and adipose tissue strongly suggests that is may be useful in reversing the insulin resistance associated with the development of GDM."
Therefore it seems logical for women at strong risk for gd to incorporate daily or every-other-day exercise into their daily routine (pending health provider approval, of course). The exercise does not need to be high-intensity; a simple 20-30 minute walk a day is useful. Swimming, water aerobics, or prenatal yoga are also good. Go at the pace that seems comfortable to you, and if you get tired or experience contractions after you get pregnant, don't hesitate to take a rest and then continue later, or stop if needed. You will probably also find that the first 10 minutes are the hardest; the motivation is low, the bones and ligaments tend to ache late in pregnancy, you are tired, etc. But most women find that if they can last through the initial unmotivated stretch, they feel better in the long run (LESS achy, less tired, etc.) than if they don't follow through. If you truly feel bad, of course, DO stop, but usually lasting through or taking little rests and then continuing is a more beneficial course.
But however you do it, do try to get out and get REGULAR exercise. Although some days this is a pain, it beats having all the interventions for gd!
Once You are Pregnant: Nutrition
If you are already pregnant, it is important to focus on extremely healthy habits as soon as possible. Although it's best to do this from the very beginning (or before), it's never too late to start. Although official studies are lacking, there is some good anecdotal evidence that eating on a gd food plan long before gd even occurs might help minimize or prevent gd. (See Kmom's story!)
A gd foodplan is really not that different from the pregnancy nutrition guides out there in terms of amounts; it's more the TIMING and PATTERN and FOOD COMBINATIONS that are different. The focus in a gd food plan is on breaking up the food intake into smaller portions and spreading them out throughout the day, and in taking in protein with your carbs. The advantage of this is that it minimizes the demands on your system for dealing with the blood sugars (bG), does not overtax your insulin response, and provides a more consistent amount of energy so you do not have strong swings of bG, high and low.
Some suggestions for nutrition include:
1. Eat smaller meals and snacks, but eat more frequently ('grazing').
This is extremely important to do. You will need to eat lightly about every 3 hours. Your total intake over the day may be the same as other pregnancy food plans, but it will be spread instead over 5-6 meals/snacks, instead of concentrated in 3 larger carb-heavy meals. This allows for more efficient response by your system, avoids an overload of too many carbs at once, and avoids large swings in blood sugar from high to low and back again. Some feel that it is this SWING from highs to lows and back again that may predispose susceptible people to gd later in the pregnancy. It is your goal during pregnancy to keep your blood sugar as even as possible throughout the day and night. (This is called euglycemia.)
2. Make your eating patterns even and consistent; never skip meals or go for a long time without eating.
In order to help keep your blood sugar as even as possible, keep your eating patterns very even and consistent. It's especially important not to skip meals or to go for a long time without eating. Many women make the mistake of skipping a meal, then sometimes eating a larger meal later on. This makes the blood sugar swing from too low to too high. Eating a small snack every few hours helps prevent this, but it's important to keep the intake and schedule consistent from day to day.
It's also important not to fast too long overnight; between 8-10 hours is about right. If you go longer than that, the body's blood sugar levels dip too low and the body must access the sugar stored in the liver (glycogen) and burn fat stores for energy, producing ketones which are not good for the baby. Eat a good snack shortly before bedtime (see below) and then fast for no more than about 10 hours. Some women do better with 8 or 9 hours, so experiment a little bit and do what seems to work best for your body.
3. Always eat proteins with your carbs.
Protein slows down the absorption of carbs, and makes the energy available more evenly and for a longer period of time. It is extremely important to have protein whenever you have more than one carb. Protein is particularly important with the morning meal and with the bedtime snack. You don't need huge amounts of protein, just frequent small servings with your carbs. Over the day, this will total up enough to help baby grow optimally and to possibly help avoid the risk of Pregnancy-Induced Hypertension (PIH, a.k.a. pre-eclampsia).
One of the harder things, though, is finding convenient, varied forms of protein in small amounts. String cheeses are convenient, portable, and low-fat; hard-boiled eggs are a good portable choice too (you don't need to worry about cholesterol intake during pregnancy unless you have previous high blood lipids). Other options include chunks of turkey ham (cube it up ahead of time), slices of deli meats (but be careful of those that add sugar or nitrites), slices of hard cheeses, servings of cottage cheese, peanut or nut butters, and eggs in other forms. Lentils and beans are a great source of protein, too, but count as a starch AND a protein in one. However, they make your blood sugar rise the least of all carbs, so they can be an excellent source of protein and carbs combined.
4. Eliminate ALL sugar from your diet during pregnancy.
Although it may not be easy, you would be wise to cut ALL sugar consumption or allow only an extremely occasional treat. Sugar is a simple carbohydrate that is processed extremely fast, creating a strong challenge for your system. When a sugar reaction is combined with the insulin resistance that happens naturally from placental hormones, it can overwhelm and fatigue your system. It also makes your blood sugar spike high and fast, then causes it to crash later, and then precipitate an intense craving for more sugar (a vicious circle). It is not only the high blood sugar that is the problem, it is the swing from highs to lows that cause a problem. Although many women find it hard to do, it IS best to eliminate or nearly eliminate sugar from your diet in pregnancy. Many midwives report that simply eliminating sugar and refined carbs (and eating more frequent protein) is enough to prevent most cases of gd in their practice.
5. Eat when you are nauseous, even though you don't feel like it.
Most doctors will tell you that it doesn't matter in the early days if you eat or not when you are nauseous and that baby will be fine regardless. However, it is quite possible that this advice can lead some people into a chronic pattern of low blood sugar for long periods (which makes the nausea worse), then strong swings upwards when you do eat and your body suddenly has to process all that energy. Again, it may be the swings of blood sugars that precipitate the gd problem, along with insulin resistance. {Nausea and uneven blood sugar was a definite factor for Kmom, first-time around!}
Hint: It is very difficult to eat when nauseous, but many women find that forcing themselves to eat a small amount of protein every 3 hours or so actually helps ease the worst of the nausea, once they get past the difficulty of eating. If you are feeling nauseous, it is usually your body's signal to eat, as contradictory and difficult as that may seem. You don't have to eat great amounts, but take a small amount of protein and if possible, a small amount of carb (crackers and cheese, bread and peanut butter, etc., or simply a piece of string cheese). So although eating every 2-4 hours does not prevent all morning sickness, it may help keep yours from getting out of control, and keep it shorter and more manageable. If you have trigger foods, substitute others that can give you the necessary vitamins and minerals. {Kmom couldn't look at vitamin A veggies in one pregnancy without retching; cantaloupe was a good substitute.} You may not be able to eat completely normally, but do try very hard to eat every 2-4 hours in small amounts. Be sure to have a good bedtime snack, complete with protein (see below), and review the ideas for dealing with nausea listed in the websection on Dealing With Nausea.
Anecdotally, Kmom has found that many women with gd experienced major bouts of long-lasting or severe nausea, and that often this improves once on a gd eating plan. This seems to support the idea that low blood sugar and wild swings of blood sugar tend to be associated with development of gd. Force yourself to have at least some intake, and make it as healthy as you can. {Kmom had strong nausea for *7* months of her first pregnancy and a resulting very erratic intake; it probably added to the gd. In her subsequent pregnancies, eating every 3-4 hours and emphasizing protein intake kept the nausea levels much more manageable and limited to the first trimester. Frequent 'grazing' won't prevent all nausea, but it can help keep it from getting out of control or perhaps adding to a tendency towards gd.}
6. Emphasize nutrient-dense foods and quality over quantity.
Dr. Sears, author of The Birth Book, feels that you don't really have to eat much more in pregnancy, but you do need to eat better, meaning more high-quality and wholesome foods. When you examine the lists of foods that are highest in the various nutrients needed in pregnancy, you will find several foods that are common to many lists. Emphasize these foods in your diet.
Every day, have a salad or suitable substitute. Emphasize nuts and seeds, fresh fruits and vegetables, and whole grains like brown rice and wheat bread. Increase the number of times a week you eat legumes like lentils and dried beans. Focus on the fruits and veggies that are the MOST nutritious, such as spinach, broccoli, sweet potato/yam, carrots, potatoes (with skin), asparagus, kiwifruit, oranges, cantaloupe, papayas, mangoes, and strawberries. Also try to eat them as fresh as possible. The closer to nature they are, the more nutrients they contain for the baby.
7. Cut back or be very cautious with highly refined or simple carbs; increase fiber intake.
Eliminate junk-food and refined foods such as white breads, highly processed baked goods, pop, french fries, etc., and minimize foods such as cold cereals, hamburgers, and fast foods. Studies show that higher-fiber foods tend to produce less of a blood sugar response than refined foods, so when you choose foods like rice or bread, be sure to have brown rice or whole-wheat bread. It's not that you can't ever let an 'impure' food cross your lips in pregnancy, but you REALLY need to cut back junk foods and highly refined products as much as possible. Although some pregnant women can tolerate these foods, the more at-risk for gd you are, the more careful you need to be about these! Some midwives report being able to help women prevent a recurrence of gd simply by cutting the "white" foods out of their diet---white rice, white bread, highly refined foods with lots of white flour, etc.
Be aware of simple carbs vs. complex carbs in your diet, and be very cautious about consumption of the simple carbs like fruit juices. Sweetened and unsweetened juices should be avoided as much as possible since they stress the system just as strongly as regular pop does. Many women (including Kmom in her first pregnancy) increase their consumption of fruit juice during pregnancy thinking that they are being healthy, only to find out later that they created intense blood sugar spikes and insulin response by drinking lots of fruit juice. Drinking even moderate amounts can cause very strong spikes of bG, and the nutrition benefit is not that significant. It is better to eat the fruit itself, which has fiber to help slow down the bG spike, and more nutrients to boot. Although you can probably have occasional small amounts of fruit juice, you should most often choose water instead. (Try drinking it ice-cold---it tastes best that way!)
Be cautious as well about the amount and timing of milk consumption, since it also acts as a simple carb. Milk can be an appropriate part of a pregnancy diet if you desire it, BUT it can also cause strong bG spikes in women that are especially prone to insulin resistance. Because it has fat and protein to help slow down the process it is better than juice, but it does produce a significant response. For example, when insulin-dependent diabetics have an episode of very low blood-sugar (and are in danger of passing out, etc.), the experts often recommend either juice or milk as the treatment of choice. This shows that women who may be prone to blood sugar problems in pregnancy should be very cautious in their use of fruit juices and milk.
Some women whose bG is very sensitive find that it's best to avoid milk in the morning when bG tends to spike highest. Other women can handle it fine then, as long as protein is eaten too and the rest of breakfast is not very carb-heavy. If you strongly desire some milk, it's most optimal to have it later in the day (i.e. before bed is good) and be cautious about combining it with other carb-intensive foods. Generally speaking, you should be cautious about adding the carbohydrates in milk to the carbohydrates in a meal as it can create a carbohydrate overload at one time. And in general, avoid mixing fruits and milks together, since they both tend to raise bG quickly and strongly. Finally, if you have a history of large babies (9 lbs. or more) in your family or your partner's family, you might want to be particularly cautious in the amount of milk you consume. Although not all experts agree, many midwives feel that drinking a lot of milk tends to exacerbate a tendency towards larger babies among women prone to that. Foods like cheese, yogurt, almonds, calcium-fortified O.J., green leafy veggies, and supplements can give you the extra calcium you need, but be very cautious about too much milk.
8. Limit carb intake at any one time; know the carb loads of typical foods.
One serving of carbohydrate, for example, equals 15 grams, which is about what you find in one piece of bread. Most meals should be limited to about 45-60g of carbs, or 3-4 servings. That means ALL your carbs, mind----fruits, milk, starches, starchy veggies, sweets, juice, etc.! So it's very easy to overload on carbs at any one meal. Become adept at counting carbs so that you can roughly estimate the amount being consumed at any one time, and be sure that you always have some protein as well if you take in anything more than 1 carb (15 grams). If you are at particularly strong risk of gd, you might want to be even more cautious and limit your intake to 30-45 g of carbs at any one time (2-3 servings), and be especially cautious of 'danger' foods.
For example, if you had a small potato, a roll, a glass of milk, an orange, and some corn or peas with your steak dinner, you would have already exceeded the carb allowance. Put all together, these add up to 5-6 carbs (a roll often has 2 carbs, or 30g). You want to keep your intake to 45 g or so on average, or about 3 carbs most of the time. So instead, you might want to have the potato, the orange, some broccoli, and some peas with your steak. That way you get the benefit of all the vitamin C in the orange, potato, and broccoli (which tends to increase the absorption of the iron in the steak), 4 nutrient-rich veggies and fruits to add to your daily total, and no milk calcium to interfere with the iron in the steak. (You can have the milk instead later that night at bedtime, along with some protein, if you really crave having some milk.)
You should be very cautious with 'danger foods', foods that are very carb-intensive and can cause large swings in bG. Foods such as fruit yogurts, muffins, croissants, bagels, bean burritos, cold cereals, etc. tend to contain high amounts of carbs and raise blood sugar strongly. It's not that you can't EVER have these foods, but you should be extremely cautious in their use, and be sure to read labels so you can accurately estimate the amount of carbs you are having.
For example, most fruit yogurts contain about 45g of carbs, or the equivalent of 3 carb servings in one small container. Muffins often contain a huge 45-60g, since they usually have flour, fruit, and sugar, all carbohydrate ingredients. Bagels usually contain about 45 g too, and if you have one with fruit in it, the totals can go even higher. Cold cereals tend to be extremely carb-intensive, and many people eat larger servings than what is given on the label. Then combine the cereal with the carb in milk and you have an extremely carb-intensive meal. If you want to have cereal, try to choose the least carb-intensive ones (read the labels!), avoid the ones with fruit or that have sugar near the top of the ingredient list, and only have a small bowl. Also consider having it later in the day instead of in the morning (when blood sugar tends to be highest).
Also remember that all carbs are not created equal. Some types of carb tend to cause a much stronger blood sugar response than others. For example, white rice creates one of the strongest responses in most people, sometimes greater than that of sugar! White bread also creates a strong response, as does pasta. So if you want a starchy food at your meal, most people generally do better with a potato (in the skin) than with a roll, or by having brown rice instead of white rice. Sweet potatoes sound like they would create more of a problem, but most non-diabetics can handle them just fine (if they are eaten without the brown sugar and marshmallows!), and they are one of the most nutritious vegetables around. Beans, lentils and other legumes DO have to be counted as carbs, but they are so high-fiber that they tend not to create a very high blood sugar response compared to breads, etc, plus they are high in protein and many other valuable nutrients such as folic acid. It's not that you cannot ever have a roll, white rice, fruit yogurt, or pasta, just that you should eat them infrequently, be VERY cautious with their serving size, and be cautious what else you are eating with them.
Also be aware of hidden carbs; some foods that don't seem like carbohydrates actually are. Many canned spaghetti sauces contain carbs. Lentils and beans are an excellent food but they count as both a protein and a starch, due to their carb content. Peas, corn, yams and potatoes offer plenty of nutritional value, but must be counted as a starch as well as a vegetable. Many diet foods, like sugar-free pudding, also count as a carb serving; read the label to know for sure. You don't have to avoid corn or beans, just be sure to count them as carbs too.
In general, it's best just to avoid or strictly limit junk foods, simple carbs, and the most carb-intensive foods completely in pregnancy. Some women can handle intense carb loads just fine, but if you are in one of the higher-risk groups for gd, limiting these foods is probably a good idea. Read labels carefully for the serving size and carb content of each food; you'd be surprised at how helpful this can be! Remember, one serving carb equals 15 grams, and you generally want about 45g per meal.
9. Have a good bedtime snack (with protein) to help stabilize night-time blood sugar.
Many women suffer unnecessarily with very strong pregnancy nausea, and this is often caused (or made worse) by a dip in blood sugar overnight. It has been Kmom's observation that many women prone to insulin-resistance or borderline blood sugars tend to be especially prone to problems with nausea, creating a vicious circle that only gets worse. Although it's not usually possible to eliminate all pregnancy nausea, it is usually possible to moderate it and keep it from spiraling out of control. One of the ways you can do this is to eat some protein every 3 hours or so, as noted above, and also to have a good bedtime snack that also contains protein.
In pregnancy, the body tends to raise its blood sugar reaction to eating to get more energy for the growing baby and to use up MORE blood sugar overnight for a steady energy supply, resulting in a lower blood sugar then. This means you have to watch your intake during the day to be sure you don't overload your system with too much carb at once, and to eat a bit more at night to be sure that your blood sugar doesn't drop too low overnight.
So it's important for women with a strong tendency towards insulin resistance to have a good snack before bedtime, and it's vitally important that this snack contain protein to help the blood sugar remain more steady throughout the night. Otherwise, you tend to get a high spike from the carbs you consume, and then a blood sugar crash in the middle of the night as the energy runs out. Your blood sugar then either gets too low (causing a lot of morning nausea) OR your body compensates by accessing other energy sources such as body fat, the by-products of which are ketones, which in large consistent amounts can be harmful to the baby. So it's a very important preventative step to have a good bedtime snack with protein.
This snack is not a meal and doesn't have to be large; 1-2 servings of protein, and 1-2 servings of carbs is enough for most women. If you want to, you can have your milk at bedtime as one of your carbs. A typical snack might be 2 pieces of string cheese, a small glass of milk, and some graham crackers a half hour or so before bedtime. You don't want to eat just before bedtime, but neither do you want it to be hours beforehand, either. Time it so that your morning meal occurs about 8-10 hours after your bedtime snack. So if your bedtime is about 10:30 p.m., eat your snack around 10 p.m., and then your morning breakfast at about 7:30 or 8:00 a.m. Or if you are a night-owl like Kmom, move those times back. This is not rocket science; timings don't have to be exact, but it is generally a good idea not to fast for anything less than 8 hours or anything more than 10-11 hours.
10. Make your breakfasts very small and conservative, and be sure to have protein.
There is an early morning rush of hormones that make most pregnant women more insulin-resistant in the morning. In addition, the typical American breakfast is extremely carb-intensive and often does not have much protein in it. Given the tendency for blood sugar to be react the strongest in the morning, this is a disaster waiting to happen for women at-risk for gd.
Keep your breakfasts small, omit milk and fruits as much as possible, and be sure to eat protein with it. It may seem strange to have such a small breakfast, but if you get hungry, you can eat a snack 2-3 hours later to help give you enough energy until lunch. Your breakfast should have a starch serving, a fat serving, and most importantly, 1-2 PROTEIN servings, which will serve to slow down the carb surge from the other foods. Try to avoid fruit or milk at breakfast, since these foods tend to cause quick, strong blood sugar reactions and you are least able to tolerate this in the morning. You can have these foods later in the day.
Some women may be tempted to skip breakfast entirely. This is also a disaster waiting to happen, and you should NEVER skip breakfast, especially in pregnancy. Your body must provide energy for a growing baby 24 hours a day, and reserves tend to drop overnight. If you do not eat breakfast, your body is subjected to a too-long fast, which is bad for both you and the baby. This will also tend to increase the occurrence, length, and severity of pregnancy nausea. Basically, the rule of thumb in pregnancy is to NEVER skip meals, no matter what. You don't have to eat a lot, but you do need to eat regularly (see above).
Kmom's story: I thought I was being so healthy at breakfasts in my first pregnancy! I often skipped breakfasts or lunches some days pre-pregnancy, so once I was able to eat in the morning again in pregnancy, I concentrated on eating muffins and juice for breakfast, or raisin bran and a glass of O.J. for breakfast. Little did I know (because no one had told me!) that this was one of the worst breakfasts I could possibly eat in terms of gd risk! A ton of carbs, lots of fruit, plus fruit juice and/or milk---augh! And NO protein food to help slow things down! And I thought I was eating a 'good breakfast'. Sure enough, I was having major blood sugar spikes in the morning, and ketones overnight. It took quite a while to get my blood sugars more even through the day once I was diagnosed with gd; in subsequent pregnancies I was able to prevent this problem completely by just being more careful. An ounce of prevention really is worth a pound of cure!
There are many pregnancy food plans out there, and although most share the general basics, they do differ in a few ways. For example, some are very high-carb, requiring 6-11 starches per day, resulting in a very high carb content of 60% or more carb. Others sometimes require too little protein; pregnant women should probably consume at least 80-100g of protein per day (counting the protein in all your foods, however, not just the meats). A comparison of many different programs is on the FAQ on pregnancy nutrition on this website. However, here is one possible sample plan that would probably align with many gd food plans. There is a similar (but not exactly the same) program also presented on the GD: Nutrition Questions FAQ on this website as well.
Remember, however, that this is NOT a prescription for you, and it is not medical advice. If you are at high risk for gd, you would do well to have a consultation with a registered dietician in order to get an individualized food plan specially designed for your special needs. This food plan hopefully represents a fairly sane compromise between some of the more extreme pregnancy nutrition programs out there, and tends to be lower carb and higher protein in recognition of the special needs of a person who might tend towards gestational diabetes. However, it may need to be tweaked to meet your specific needs, and this is best done by an expert, trained in diabetes and nutrition concerns.
This plan is not written in stone. It simply represents one possible sample plan. You can adjust things somewhat to suit you. Perhaps you prefer eating 5x per day instead of 6x, or perhaps you prefer not to drink milk at all. These can be accommodated. However, if you adjust things too radically, the necessary amounts of carb, protein, calories, and nutrients may or may not get met. Again, this is something that a registered dietician can help you with. They are experts at adjusting programs to meet the individual needs of each person. Feel free to tinker with this plan, but remember that this may increase the amount of carbs or whatever in the plan. If you want to make lots of alterations, consult a registered dietician so a plan that is balanced and sane can be found for your specific requests.
That's not to say that all registered dieticians would agree with this plan or that all of them would even come up with the same plan for everyone! Some are much more knowledgeable about gd plans than others, and sometimes gd moms are given 'gd' food plans that really don't follow the 'gd food rules' that most research espouses (i.e. don't mix milk, fruit and starches at the same meal, limit carbs to 45-60g at any one time, get between 40-50% carbs, etc.). So although this food plan generally follows most guidelines, it's possible that you might be given something that conflicts with what's written here. This simply represents the diversity of opinion on gd treatment protocols out there today.
Specifics on the Sample Plan:
How the plan might be divided up during the day:
Again, this is just one sample plan, meant only to give a basic idea of how the earlier nutrition suggestions might be implemented throughout the day. It can be tweaked to meet each individual's needs or preferences, but Kmom strongly suggest consulting privately with a registered dietician in order to tailor a plan to your specific needs and the latest research.
Other Common Nutrition Questions
Should I diet during pregnancy?
In a word, NO! Well, actually it depends on what you mean by 'dieting during pregnancy'. If you mean cutting back on calories and restricting your intake, no, this is probably not good for you or your baby. If by 'dieting during pregnancy' you simply mean emphasizing healthy foods, cutting back on junky stuff, yet still eating sufficiently, then this is probably harmless as long as you have sufficient calories. But most of the time, most people use 'dieting' in pregnancy to mean cutting back significantly in calories, fat, carbohydrates, etc.
Although some doctors will tell you that this is fine during pregnancy, it is not! Your child needs full nutrition every single day, and so do you. Growing a baby is hard work, and although it can be done on less-than-optimal nutrition, Mother Nature has a way of making you pay for it later on. And if you eat a diet too low in calories, your body tends to divert the protein it takes in from important baby-making tasks and use it for daily energy requirements instead. You need a diet rich in protein, fiber, and varied nutrients in pregnancy, and this diet must have adequate calories as well. Just what 'adequate' calorie levels are, however, is under debate.
Nobody really knows exactly how many calories in pregnancy are really necessary. Americans tend to overconsume calories as it is; it's hard to say reliably just how many are needed in pregnancy. Most pregnancy books that specify caloric totals in pregnancy use 2400 or 2500 calories as their guideline (although if you figure up exactly how many calories their specific recommendations actually add up to, it is often less than what they recommend). Most women probably don't need 2500 calories in pregnancy, but somewhere around 2000 calories is probably adequate for most.
The wrinkle when discussing blood sugar, pregnancy, and calories is that lower caloric totals tend to encourage better blood sugar totals. Because of this, many 'experts' recommend very low totals for obese women who are diagnosed with gd (as if babies of heavy women require any less energy than those of thinner women!). Some experts regularly put heavier women with gd on 1500-1800 calorie diets, and a few researchers have used 1200 calorie diets. However, these are based only on their perceptions of what heavy women need, and do not adequately test for safety. Lower calorie diets do tend to lower insulin needs, BUT they may be unsafe in pregnancy. What is most disturbing about these recommendations is that NO attempt is made to determine the long-term health of the babies given these low-calorie approaches. Researchers check to be sure the mother is kept just above the level of spilling ketones in her urine (a by-product of burning fat stores which may be harmful to the baby in large amounts), and congratulate themselves on their approach if fewer women need insulin while on these diets. After the baby is born, however, no one checks to see if the baby is as healthy as babies whose mothers consumed normal diets, nor does anyone do any follow-up to see if there are any long-term effects of shortchanging the fetus. In short they assume hypocaloric diets are better for mother and baby, but they do not check that hypothesis at all, nor can they show lack of harm in that approach. This is extremely poor science!
To err on the side of safety, most dieticians these days do not use 1500-1800 calorie recommendations. (See the discussion and specifics on this in the web section on GD: Nutrition Issues.) Most women with gd, heavy or not, are given between 2000-2300 calories. Kmom feels it is probably not best to obsess over exact numbers of calories, but that emphasizing good, nutrient-dense food and cutting out nearly all junk food should help keep caloric totals reasonable without going too far in either direction. In other words, don't DIET in pregnancy, but do strongly emphasize good healthy reasonable eating.
Should I follow a low-fat diet?
No, you want to follow a moderate-fat diet in pregnancy. Extremely low-fat diets are not good for women who are insulin-resistant in pregnancy, since fats also perform the valuable function of slowing down blood sugar rises. Eating some fat helps your blood sugar. Furthermore, a reasonable amount of fats help the body absorb some of the more important pregnancy nutrients; a diet too low in fats tends to inhibit your ability to fully absorb these nutrients, which are important. However, a really high-fat intake is also not desirable, as it may increase insulin-resistance or cause you to gain too much weight in pregnancy. So basically, moderation is the key.
Most dieticians recommend an intake of about 30% of calories from fat during pregnancy, 20% when not pregnant or at risk for problems like heart disease. 30% in pregnancy is not hard to achieve; there are fats in the foods you eat so if you add one serving of additional fat at each meal and you probably are in about the right range. You probably already know the routine; use skim or low-fat milk, lower-fat meats and cheeses most of the time, take the skin off chicken and extra fat off beef, etc., so that you can indulge in a bit more other fats at meals. Try to emphasize monounsaturated fats (olive oil, olives, nuts, etc.) over saturated fats and polyunsaturated oils etc., and try to stay away from trans-fatty acids like many margarines (there are some out there without trans-fatty acids; read labels). However, this is not a diet; you don't have to abstain completely from foods with higher fat contents, just be moderate about them.
Should I follow a low-carb diet in pregnancy?
No, a moderate-carb approach is better. Although monitoring your carb intake is a good idea (especially for women who tend towards insulin resistance), too low a carb intake can also be bad, since it tends to cause ketones (a by-product of burning fat stores for energy instead of carbs). Large consistent amounts of ketones are thought to be harmful to the baby, and this generally occurs when the mothers skips meals, does not consume enough total calories, or does not consume enough carb in her diet. GD studies have experimented with reducing the carb intake in gd patients, and generally find that high-carb levels do cause high blood sugars in susceptible women, but too-low carbs or calories tends to create too many ketones. So the key is to find a balance.
It is not scientific, but it is Kmom's anecdotal observation that the mothers she has known who have been on aggressively low-carb diets before pregnancy have almost all gone on to very significant cases of gd during pregnancy, with many problems controlling their ketones in particular. And continuing these very low carb programs into pregnancy is particularly worrisome. Most of the popular low-carb diets are too low-carb for pregnancy and are not recommended for use in pregnancy.
The Zone diet is about 40% carb, which is a tad low for pregnancy. Some women can tolerate 40% carb in pregnancy without harm, but for some it tips them into ketosis and is not a good idea. So generally speaking, without a registered dietician's supervision and frequent testing for ketones, it's best to err on the side of a bit more carbs. About a 45% carb plan is probably fine; the "What to Expect" pregnancy plan is about 47% carb (just ignore all the idiotic fat-phobic remarks they make in the text), but it's important to remember that the WAY you schedule the food during the day is as important to a moderate-carb approach as the totals you consume during the day. Many of the other pregnancy nutrition guides are extremely high in carbs (many contain 60% or more carb); while some women tolerate this just fine, if you are at high-risk for gd you might want to choose one of the more moderate plans. For an analysis of the carb etc. content of many of the leading pregnancy nutrition books, please see Kmom's websection on Pregnancy Nutrition.
Are diet foods like sugarless pop and diet puddings okay in pregnancy?Well, this depends who you ask! Basically, the official answer from dietician's groups and doctors is that small amounts of foods sweetened with aspartame are okay in pregnancy, like a serving a day or so (most other sweeteners should be avoided). Kmom has strong reservations about aspartame in pregnancy and personally chooses to abstain from it, but there is little conclusive proof available either way. Each woman must decide for herself what she will do. Since there is not conclusive *proof* that aspartame is free from harm in pregnancy and because it's a substance not normally found in nature, Kmom generally feels that it should be avoided to be safe, but most doctors would tell you not to worry about it. If you decide to have some, Kmom would urge you to have it in very small amounts only, and only very occasionally. It's probably prudent to be more cautious than not in pregnancy as a rule. For a more complete discussion of this issue, see the websection on GD: Nutrition Issues.
What about food supplements like chromium picolinate to help lower my blood sugar?
Some research seems to show that chromium deficiencies can help predispose a person to blood sugar problems, and some research studies seem to indicate that taking chromium picolinate can help improve blood sugar levels in diabetics. However, not all studies have found it helpful; it's speculated that it's probably most helpful in people who are chromium-deficient and not very helpful in those who are not. A couple of small, limited studies have found that once gd has been diagnosed it can help maintain better blood sugar control, although these studies did not address the safety of this approach very adequately. No study has addressed whether doses of chromium picolinate taken prophylactically can help prevent gd, but some people have speculated that it might.
Because no one knows much about the efficacy and safety of taking chromium picolinate during pregnancy, Kmom's opinion is that it is better to be safe than sorry, and that chromium supplements should probably be avoided during pregnancy. However, she does know that some women at extremely high risk for gd (i.e., those with PCOS plus other risk factors) have taken chromium supplements during pregnancy with the approval of their OBs. Others, however, have been advised not to. This is a personal choice that each woman must decide for herself, but it's probably best to err on the side of safety if you are not sure what to do.
As a side note, some concern has been raised about the safety of chromium picolinate; some people recommend chromium GTF as a better choice if you do choose to try chromium supplementation. Before taking any chromium product, you should probably try to search for the latest research on the subject to check for any new safety concerns or alerts.
"An ounce of prevention is worth a pound of cure." --traditional proverb
Although most of the ideas listed here are not very difficult to integrate into your life, it can't be denied that it can be a pain in the neck to do them. Pregnancy has enough stresses; many women feel that they do not want to add any more by trying to schedule out their eating so much, or by worrying whether they've had enough protein to counterbalance their carbs, or by trying to count up the amount of carbs they are consuming at any one time. Some pregnant women will not choose to try any of the ideas here, and that's their choice. However, Kmom's own experience has taught her that prevention now is a lot better than tons of intervention later.
Gestational diabetes is a controversial diagnosis, and treatment for borderline cases may or may not help. In some cases, critics charge that the mere fact of a 'gd' label worsens outcome and may be harmful. But even if the gd diagnosis is legitimate and beneficial, it's true that women diagnosed with gd undergo a great deal of extra intervention and hassle. Regardless of whether gd diagnosis and treatment helps or hurts, extra intervention IS virtually certain. If it's within your power to act NOW to potentially avoid this label and all that intervention, it is probably in your favor to try.
Furthermore, if you were to develop a severe case of gd, these ideas could only help you. In truly severe cases of high blood sugars, treatment almost certainly helps. Primary among these treatment protocols is dietary intervention, with exercise as a complementary therapy in appropriate women (and insulin if needed). If you were to be diagnosed with gd while proactively watching your nutrition, you would have a head start because you'd be doing a lot of the dietary guidelines and exercise already, you might have kept your case of hyperglycemia from really getting out of control, and you might be able to avoid insulin treatment as a result. Or even if your case were severe enough to need insulin, keeping things more under control from the beginning might prevent your baby from developing some of the rare but possible risks, such as difficult birth due to pathological macrosomic growth patterns, neonatal hypoglycemia or hypocalcemia at birth, etc.
Most prevention regimens can involve risk/benefit tradeoffs. In this case, these are quite minimal. It is doubtful that you can be harmed by spreading out your food more evenly throughout the day, eating a good snack before you go to bed, eating a protein-rich but smaller breakfast, emphasizing nutrient-dense and high fiber foods, and eliminating highly refined and junk foods. You do need to be careful not to limit your carbohydrate intake too much in pregnancy, to get enough protein and calories in pregnancy, and of course you should consult your provider to see whether an exercise program is appropriate for you, but by and large, most of the ideas here are very low-risk compared to the possibility of gd.
No one knows for sure whether these ideas will help prevent gd; almost NO studies have been done on gd prevention, so it's impossible to say whether these will help YOU. However, they are mostly just good common-sense approaches, and are unlikely to do more harm than good. Midwives do report anecdotally that they have lowered the incidence of gd in their practice by emphasizing nutrition and exercise more, and some women who have had 'gd' in the past have reportedly been able to avoid it in subsequent pregnancies by becoming more proactive about these things from the very beginning of pregnancy on. Kmom's own experience of having gd in her first pregnancy but avoiding it in her second and third pregnancies (despite being near 40) also seems to lend credence to the idea of prevention by being very proactive.
We do know that the 'gd' label tends to involve more procedures and interventions, which may bring their own risk with them. And if gd is proven to be a legitimate diagnosis with legitimate risks, prevention of it could help lessen risks of problems for the baby. And even if you do develop gd, being proactive may help your case to be less severe and easier to manage. So it seems that simply paying more attention to diet and exercise (as long as it's done reasonably) is probably a win-win situation. Always consult your provider first, of course, but as the old saying goes, "an ounce of prevention is worth a pound of cure."
Pole, JD and Dodds, LA. Maternal Outcomes Associated with Weight Change Between Pregnancies. Canadian Journal of Public Health. July-August 1999. 90(4):233-6.
Examined wt. change between pregnancies in women in Nova Scotia between 1988 and 1996 to see if there was an association for wt. loss or gain with c-sections, occurrence of gd, or Pregnancy-Induced Hypertension (PIH). 19, 932 women were studied. Found that weight GAIN between pregnancies increased the risk for developing gd (about 1.5x relative risk), but did not find that wt. gain OR LOSS was associated with any other outcomes.
Horton, E.S. Exercise in the Treatment of NIDDM: Applications for GDM? Diabetes. December 1991. 40(Suppl. 2):175-78.
Examines the literature on physical training and regular diabetes and proposes that it may also hold benefit for gdm. "Regular physical exercise should be considered as a potential approach to the prevention and treatment of GDM."
Jovanovic-Peterson, L et al. Randomized Trial of Diet Versus Diet Plus Cardiovascular Conditioning on Glucose Levels in Gestational Diabetes. American Journal of Obstetrics and Gynecology. August 1989. 161(2):415-9.
19 women with gd (extremely small sample) were randomized into either a diet-only or a diet plus exercise group. Exercising women did 20 minutes of exercise 3x a week for 6 weeks; an arm ergometer was used to maintain their heart rates in the training range. Week 1 glycemic parameters were the same for both groups; the results began to diverge significantly at week 4. At the end of 6 weeks, however, the diet plus exercise group has much better numbers than the diet-only group (70 mg/dl fasting vs. 88 fasting; 106 vs. 187 on a 50g challenge test; and 4.2% vs. 4.7% glycohemoglobin test results). "We conclude that arm ergometer training is feasible in women with gestational diabetes mellitus and results in lower glycosylated hemoglobin, fasting, and 1-hour plasma glucose concentrations than diet alone. Arm Ergometer training may provide a useful treatment option for women with gestational diabetes mellitus and may obviate insulin treatment."
Jovanovic-Peterson, L and Peterson CM. Is Exercise Safe or Useful for Gestational Diabetic Women? Diabetes. December 1991. 40(Supplement 2):179-81.
Presumably a follow-up to the above study, with very similar results. The main difference was that this study examined the effect of exercise on contractions in the women; upper-extremity (arm-only) exercise did not produce any uterine contractions, but lower-extremity exercise tended to produce contractions. For women who find they have a great deal of contractions with walking or who are in danger of pre-term labor (i.e., women with twins or a history of pre-term labor), this finding that upper-extremity exercise is effective at improving glycemic levels while not producing contractions is important. Kmom has also tested upper-extremity exercise ('lifting' cans as dumbbells) and found that it does lower her blood sugar, though not quite as well as walking or other exercise. This study (and others like it) confirms that exercise options are available even to those who don't seem to be able to do regular exercise. (Of course, however, providers should be consulted first.)
Dye, TD et al. Exercise Cuts Rate of Diabetes in Pregnancy in Obese Women. American Journal of Epidemiology. December 1997. Summarized from a press release from Doctor's Guide to Medical and Other News, at www.pslgroup.com/dg/4a5ce.htm.
This study looked at the effect of exercise during pregnancy on the rate of the development of glucose intolerance. Little effect was found for women of average size or those somewhat 'overweight'. However, in women who were significantly obese (Body Mass Index of 33 or more; the usual recommendation for women is a BMI of <25), exercise had a definite preventive effect. Women with BMIs of 33+ who did not exercise were twice as likely to develop gd as their counterparts who did exercise. Curiously, the amount and frequency of exercise showed little difference in benefit; the important factor was the presence of absence of exercise.
Artal, R. Exercise: An Alternative Therapy for Gestational Diabetes. The Physician and Sportsmedicine. March 1996. 24(3):54-6.
A primer on things for doctors to consider when considering an exercise program for a woman with gd. Contains many cautions and caveats since some experts have expressed doubts at the lack of information confirming lack of harm to the fetus from maternal exercise (too bad they are not so demanding about proof of lack of harm from aggressive insulin treatments and early induction!). Notes that in a recent uncontrolled study, a small sample of patients with high fasting levels were placed on a mild exercise program. Only one needed insulin; the rest (who would have needed insulin without the program) were able to avoid it. None had any problems.
Bung, P et al. Exercise in Gestational Diabetes: An Optional Therapeutic Approach? Diabetes. 1991. 40(Supplement 2):182-185.
41 gd patients with abnormal fasting levels who failed a diet therapy trial of 1 week were randomized to either diet+exercise or diet+insulin. The exercise group did 45 minutes of exercise 3x per week in a lab with medical supervision. 17 patients in each group finished the study. No differences were seen between the groups in terms of blood sugar determinations, complication rates, or fetal health (remember that the exercise group did not have insulin; they achieved the same results as the insulin group WITHOUT insulin). The exercise group delivered slightly later on average (38.9 weeks vs. 38.2 weeks), perhaps because of differences in physician management (insulin-treated women are usually induced at 38-39 weeks, non-insulin women generally are induced a week or so behind this schedule).
Note: There is little direct study on this issue; most inferences must be drawn from anecdotal reports or extrapolated from marginally related research on gd recurrence, etc. Much more attention needs to be paid to this issue directly, but at this time, most researchers are uninterested in pursuing the issue.
Moses, RG. The Recurrence Rate of Gestational Diabetes in Subsequent Pregnancies. Diabetes Care. December 1996. 19(12):1348-1350.
100 women with previous gd and a subsequent pregnancy were studied in Australia. The recurrence rate was 35%. Factors associated with recurrence were an increase in weight between pregnancies, higher maternal age, and greater parity (more pregnancies). Factors not found to be associated with recurrence in this study included higher glucose level, insulin use, or fetal birth weight in the original gd pregnancy. "GDM occurs in only one-third of subsequent pregnancies. Those women who had a recurrence of their GDM were older, more parous, and also had an increase in weight between the pregnancies." Also speculates on the role of dietary modification in preventing recurrence; "learned dietary modifications applied before and/or during a subsequent pregnancy may render that pregnancy 'nondiabetic' to testing."
Dicker, D et al. Pregnancy Outcome in Gestational Diabetes with Preconceptional Diabetes Counselling. Australian and New Zealand Journal of Obstetrics and Gynaecology. August 1987. 27(3):184-7.
Followed 136 women with previous gd but normal glucose tolerance between pregnancies who were given preconceptional counseling by a diabetological team for at least 2 months before conception, compared to 154 women with gd at various stages of pregnancy (presumably first-time gd, not recurrence, so the groups are not totally comparable). The group with preconceptional counseling (including nutritional counseling and close monitoring of bG) had better glucose levels, less maternal complications, less c/s rates, less congenital anomalies, and less macrosomia and hypoglycemia.
Chromium Supplementation and Blood Sugar
Jovanovic-Peterson. Lois and Charles M. Peterson. Vitamin and Mineral Deficiencies Which May Predispose to Glucose Intolerance of Pregnancy. Journal of the American College of Nutrition. 15(1):14-20, 1996. http://www.mediconsult.com/pregnancy/journal/automation/960302009007.html
Research about the influence of vitamin and mineral deficiencies on gd and speculation on the value of supplementation for gd pregnancies. Very interesting reading but still only speculative at this time. Much more work remains to be done. To read the complete article, order the original from the journal listed above. To see a brief summary along with questions and responses, see the website listed above.
Aharoni et al. Hair Chromium Content of Women with Gestational Diabetes Compared with NonDiabetic Pregnant Women. American Journal of Clinical Nutrition. 55 (1):104-107, 1992.
Women with gestational diabetes had lower levels of chromium in their hair.
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