Exercise Reduces the Risk for Gestational Diabetes in Higher Weight Women

The Padded Lilies

Here is a recent research review that found that physical exercise reduced the risk for gestational diabetes (GD) in "obese" and "overweight" women during pregnancy.

Here is a summary of the research review, and also a discussion of how to use exercise and food timing and choices to keep your  blood sugar as normal as possible during pregnancy.

Quick View of Study Details

The authors reviewed 13 studies with a total of 1,439 participants. On the up side, they found that physical exercise reduced gestational weight gain and the risk of gestational diabetes (GD). This is good news.

On the other hand, exercise made no difference in the risk for blood pressure issues, macrosomia (big babies), cesarean rates, or premature births. This isn't bad news, but it does point out that exercise is not the panacea that some doctors hope it would be.

How significant are these findings? Well, it depends on the finding.

The weight gain finding is negligible. The difference in weight gain between groups was extremely small, about 1.14 kg. That's about two and a half pounds total. Not exactly a lot, and not enough to really make a difference in outcomes between groups. But doctors being doctors, you know they are doing cartwheels over even that. (Like 2 or 3 pounds makes a big difference in complication rates.)

However, the difference in risk for GD was more substantial. The relative risk of getting diagnosed with GD was 0.71 in the groups that had more exercise. That's nearly a 30% cut in risk for getting GD, which is significant. That should be paid attention to by people of size and their medical professionals.

The strength of this review was that it didn't just rely on results from one or two studies. They reviewed thirteen studies, which makes for stronger conclusions because the results are less likely to be from chance.

One weakness of the review is that 1,439 participants is a bit small for 13 studies. That means a lot of the individual studies were on the small side, and small studies run the risk of biasing the results. The review also noted that there was little information on newborn outcomes and that future studies should account for these concerns in their study design.

These are all important points. Better studies with more participants and tracking of neonatal outcome are needed. But what we have so far suggests that exercise is helpful in larger women.

Pregnancy Exercise for Plus-Sized Women

Women of size vary in their utilization of exercise. It's a myth that fat people never exercise. Some do lots of exercise, some don't do any, while most are somewhere in the middle. Here are some practical suggestions for increasing exercise in pregnant women who recognize the importance of exercise.

Exercise doesn't have to mean running marathons or even running at all. Forget the little skinny doctors who tell you that the only "real" exercise is running. Walking is one of the best exercises for pregnant folks, and it's much easier on the knees and hips. All you need are comfortable clothes and supportive shoes. Just go outside and take a walk around your neighborhood.

If your neighborhood is unsafe or not conducive to walking, walk around your yard or inside your house. Or get a second-hand treadmill or exercise bike for cheap off of eBay and use that inside.

Swimming or water aerobics is another exercise that works particularly well for women of size. While it's a pain to get in and out of a swimsuit when extremely pregnant, the buoyancy in the water is incredibly soothing to larger bodies. And water immersion has a strong beneficial effect on reducing swelling near the end of pregnancy, which can be quite helpful. Plus it just feels great! 

Water immersion can be particularly important for women with lipedema. The hormone changes of pregnancy can sometimes cause lipedema to get worse. But the pressure of having your legs underwater forces fluid back into your lymph system and helps it flow more freely. Remember, the lymph system doesn't have a pump like the heart directing it; it relies on exercise to improve lymph flow. If you have any degree of lipedema, it's especially important to be in water as much as you can. Even if you don't swim, just walking around in the pool is helpful.

Prenatal yoga can be another excellent choice. It's not as aerobic as other forms of exercise but the stretching and strengthening can be very helpful. The relaxation poses at the end of most classes are great for helping blood pressure and stress levels. And prenatal yoga classes tend to be more size-accepting and tolerant of different fitness levels than regular yoga classes.

If the weather outside keeps you from getting your usual exercise in, try walking or dancing around your house, going up and down the stairs, or some vigorous vacuuming. Even just using some cans to do a set of arm curls can help. [Don't laugh! I did all of those things during icy weather in my pregnancies, and even just vacuuming showed a difference in my blood sugar readings. These things helped me keep my blood sugar normal.]

If you haven't exercised much recently or are out of shape, start with what you can do and don't judge yourself about it. Start slowly, then increase the amount and frequency of what you are doing. Building a regular time for exercise in your daily routine is helpful. If you miss a workout, don't stress over it; just get back into it as soon as you can. Remember, any exercise is better than no exercise.

If you already exercise regularly, good for you! Give yourself props for what you are doing. Consider intensifying your routine by adding more sessions or changing up the kind of exercise you do. Keeping it fun helps keep it a part of your life.

Sometimes people sabotage their exercise by focusing on the wrong things. They compare themselves to others as they exercise, they feel self-conscious in front of others, or the peanut gallery in the brain keeps a running commentary of negative remarks. Put aside the negativity. Do what you can and don't beat yourself up about your fitness level, your looks, your shape, or whatever your personal demons are. Don't indulge in negative self-talk but instead focus on your improvement. Think or say body affirmations or pregnancy affirmations during your workouts. The repetition of positive affirmations during exercise can be powerful.

Exercise and Food for Managing Blood Sugar

As the study review shows, exercise can be an important part of managing blood sugar in pregnancy for women of size. However, there are ways to increase the effectiveness of exercise even more.

These are suggestions taken from the experiences in my own four pregnancies and from helpful advice from medical professionals to me and others. In my first pregnancy, I had a marginal glucose test result and was diagnosed with GD. I was put into a program to learn how to manage my blood sugar and given a glucometer. My pregnancy went fine and my baby was healthy, but that diagnosis made me subject to many more interventions than I truly needed. So I became determined to be as proactive as possible for any future pregnancies.

In my next three pregnancies, I never had GD again, despite being about the same size each time and getting older. I didn't change my weight or what I ate, but I did change how much I exercised and the food combination and timings of what I ate. Just doing that helped me avoid GD again, but I never took it for granted. I always considered myself borderline to be cautious, and I used my glucometer regularly every day to help make sure my blood sugar was staying normal.

If your family history (strong history of diabetes), prior medical history (prediabetes or prior GD), or medical condition (PCOS or reactive hypoglycemia) put you at extra risk for GD, then you should probably consider buying a glucometer and measuring your blood sugar regularly. That will give you information to guide you in what your "danger times" are, how you respond to various foods, and when adding exercise would be most beneficial. Glucometers are pretty affordable and can be bought at your local pharmacy. However, if money is an issue, your care provider may have one that you can borrow for free, leaving you just the cost of testing strips.

If you have a glucometer, you can see how your particular body responds to the blood sugar challenges of pregnancy. For example, some pregnant women have the most trouble after meals, while others have the most trouble with their fasting numbers first thing in the morning. The way you manage each is different.

Generally speaking, exercise intensity is less important than exercise frequency from a blood sugar point of view. It's not how hard you work out that matters most, but the regularity with which you do it.  In other words, walking even just a little every day is better for your blood sugar than a more intense workout once or twice a week. You are trying to lessen insulin resistance and make the insulin you have work more efficiently, and regular daily exercise works the best at this. Intensity is important for improving aerobic response, but frequency is the most important factor for blood sugar regulation. Try to exercise every day if possible, or at least five days a week.

Timing of exercise and smart food combinations are also important. Pregnant women tend to have several problem spots, like early mornings or after meals or certain foods. Placental hormones increase insulin resistance in order to increase the energy available to the baby. That means a meal that might not make your blood sugar high when not pregnant can result in a high reading during pregnancy. Or you get high readings from certain foods that don't normally raise your blood sugar when not pregnant.

If you find that your blood sugar is most volatile in the morning after breakfast, rest assured that this is a common problem for pregnant women. Many people do not eat protein with breakfast but consume very carb-intense breakfast meals like cereal with milk, a glass of juice and a muffin, or similar meals. Protein slows down the energy spike from a carb-heavy meal and keeps it from crashing later. So adding a protein food to your breakfast is one of the best things you can do to reduce morning blood sugar spikes. Taking a quick walk after breakfast is also great at smoothing out blood sugar spikes. Doing both (adding protein and going for a walk after breakfast) works best for blunting the post-breakfast spike common in many pregnant women.

Some women are intensely sensitive to certain foods at breakfast and can get blood sugar spikes from them in the morning, but no spikes from the same food later in the day. It has to do with the surge of placental hormones that often happens in the mornings. Some women who are especially sensitive simply cannot drink milk or juice at breakfast or even have fruit, but later in the day those foods are okay. The glucometer can help you discover whether you have problems with certain foods or at certain times.

If your blood sugar is running a little high routinely after all your meals, a couple of short walks each day after meals is helpful. Remember, shorter walks done more often is better than a longer walk every few days. If meals are your vulnerable time, then schedule your exercise times to happen after meals. Just work on getting your heart rate up for a sustained amount of time.

Avoiding heavy intake of carbs is helpful to improving blood sugar after meals. There's no need to eliminate all carbs, but avoid or minimize carb-intense foods like breakfast cereal, juice, muffins, pizza, bagels, and other obvious foods. Try to keep your carb intake to around 60g or less with each meal (a piece of bread is usually around 15g of carb). If you are not sure of the carb content of a food, look at the label. If there is no label, google it to get a general idea. If you do decide to have a carb-intense meal or snack for a special occasion, taking protein with your carbs or getting in some exercise afterwards can often improve blood sugar markedly, but don't do this often because it is easy to overdo.

Some people don't have much trouble with high blood sugar after meals, but instead have problems first thing in the morning after the overnight fast. If you have a tendency to high fasting blood sugars first thing in the morning, you need to investigate further because your approach to managing it will be different depending on its cause.

If your morning fastings are running just a bit high and you don't know why, try a substantial protein snack late in the evening and then take a short walk or workout before bed. Sometimes a little snack and exercise before bedtime is all you need to help the blood sugar normalize overnight.

Some women have high fasting blood sugar because they experience a "bounce." In other words, their blood sugar goes too low in the night so the body compensates by burning fat for energy, thus raising the blood sugar sharply to create enough energy for the baby. A side effect of going too low at night is spilling ketones, which is a by-product of burning fat for energy. A small amount of ketones on occasion is not a reason for concern, but a large amount of ketones on a regular basis is potentially risky for the baby. You can buy ketone sticks over the counter at local pharmacies if you want to keep track of that.

The best way to treat a "bounce" is to prevent it in the first place. Going too long without eating is a classic cause of a bounce. If you eat dinner at 6 the night before and then don't eat breakfast until 8 the following morning, that's a 14 hour fast. While that might be fine in a non-pregnant person, it's too long for many pregnant people. The body will respond by burning fat for energy and causing the morning blood sugar to go high. Keep your overnight fasts to 8-10 hours if you are having trouble with high fasting numbers in the morning.

Another common cause of a morning "bounce" is exercising before breakfast. You would think that this would be helpful in preventing high blood sugar, but again, it may cause you to go too low after an overnight fast. The liver produces glucagon and the body burns fat in order to give you the energy you need for the workout, but the price is that your blood sugar becomes elevated. Eating first and then exercising can solve that problem quite easily.

If you suspect you are experiencing an overnight bounce, the solution is to add a good snack before bedtime. However, the snack must be considered carefully. Adding a high-carb bedtime snack with no accompanying protein will spike the blood sugar and then make it crash in the middle of the night, setting up a bounce when the body compensates. A better bedtime snack is a protein-heavy snack with a whole-grain carb, which should give longer-lasting, more even energy that can regulate overnight blood sugar and prevent a bounce.

Some people find that they have "trigger foods" that cause high readings. For example, when I was pregnant I found that corn tended to make my blood sugar spike. I also found I could not consume cereal without a spike. If I ate protein with my cereal, it blunted the spike, but not enough for my satisfaction, so I just eliminated cereal from my intake. It was just a food I found I could not consume during pregnancy.

If you have reactive hypoglycemia (a tendency towards very uneven blood sugar), then eating protein every 2-3 hours is helpful. It keeps your blood sugar much more even and less prone to spikes and crashes. Eating protein every 2-3 hours is also great for people who are having a lot of pregnancy nausea, which is often related to unstable blood sugar. That doesn't mean it will prevent all vomiting; it won't. But it might well lessen it. Even if you throw up, go rinse your mouth, rest for a few moments, and then eat a small amount of protein. The secret is to avoid large amounts of food at once, but to graze frequently during the day, emphasizing protein foods with any carbs. That will help blunt the spike/crash cycle that can be so hard on the body and the baby. People with hypoglycemia also should eat well before their exercise routines and carry some quick energy foods with them in case they go low during exercise.

If you have tried all of these ideas and you are still getting high blood sugar numbers, you may need additional help to normalize your blood sugar. Your medical professional will help you decide whether to use medications like metformin or insulin. If you do end up needing insulin, it doesn't mean that you have failed, just that your pancreas cannot create enough insulin anymore to compensate for the insulin resistance from the increasing hormones of late pregnancy. Progesterone in particular peaks in the third trimester a month or more after the usual GD tests, so you may start out fine with dietary control and still end up needing insulin. Either way, don't feel guilty; it's just the way your body copes with pregnancy hormones.

These are just a few ideas that many women have found helpful in managing blood sugar during pregnancy. However, it's important to emphasize that not all GD can be prevented. Sometimes people still get GD no matter how hard they work at healthy eating and regular exercise. And while most people can manage their blood sugar with diet alone, some may also need medications or insulin to keep their blood sugar normal. If you get GD, don't view it as a personal failure. Just remember that with good care, most women with GD have good outcomes. Dealing with GD is just what you need to do to help give your baby the best possible start.

Take Home Message

The most important message from this review of studies is that exercise in pregnancy may be very helpful in people of size in lowering the risk for GD. 

If GD does occur, exercise plays an important role in managing the GD and minimizing its risks. So does careful consideration of food intake and timing. Getting a glucometer so you can monitor your results at home helps you manage things based on your own needs and responses. Although it's a pain to test, it really does allow you more control over the whole process and outcome.

Since doctors tend to get all uptight about gestational diabetes in higher weight women and a GD diagnosis is the beginning of many interventions, anything women can do to lower their risk for GD is potentially very helpful. Exercise is one of the most powerful interventions women can make on their own behalf.



References

Birth. 2018 Sep 21. doi: 10.1111/birt.12396. [Epub ahead of print] Effects of physical exercise during pregnancy on maternal and infant outcomes in overweight and obese pregnant women: A meta-analysis. Du MC, Ouyang YQ, Nie XF, Huang Y, Redding SR. PMID: 30240042

...The purpose of this meta-analysis was to assess the effect of physical exercise on maternal and infant outcomes in overweight and obese pregnant women... RESULTS: Thirteen studies involving 1439 participants were included. Physical exercise reduced gestational weight gain (mean difference = -1.14 kg, 95% CI = [-1.67 to -0.62], P < 0.0001) and the risk of gestational diabetes (RR = 0.71, 95% CI = [0.57-0.89], P = 0.004) in overweight and obese pregnant women. There were no significant differences in other outcomes such as gestational hypertension, preeclampsia, cesarean delivery, birthweight, large for gestational age, small for gestational age, macrosomia, and preterm birth. CONCLUSIONS: Prenatal exercise interventions reduced gestational weight gain and the risk of gestational diabetes for overweight and obese pregnant women, which reinforced the benefits of exercise during pregnancy. However, no evidence was found with respect to benefits and/or harm for infants. Consideration should be taken when interpreting these findings as a result of the relative small sample size in this meta-analysis. Further larger well-designed randomized trials may be helpful to assess the short-term and long-term effects of prenatal exercise on maternal and infant outcomes.

*For more information on troubleshooting  high blood sugar numbers with GD, read my article on it. Be aware it's from my old website (which I can no longer update), so some information is outdated, but most of it is still valid.