What to Do About Gestational Diabetes

Gestational diabetes -- a type of diabetes some women develop in pregnancy -- affects upwards of 10 percent of pregnancies each year, according to the Centers for Disease Control and Prevention. And some estimates say the number of women who will develop gestational diabetes during pregnancy is higher than that.

What Causes Diabetes in Pregnancy?

The condition occurs when the body isn't able to make enough of the hormone insulin -- which helps regulate or control blood sugar. Changes during pregnancy, such as an increase in hormone production and weight gain, can cause insulin resistance, leading the body's cells to use insulin less effectively, the CDC notes. More insulin is needed as a result.

Particularly if it's not well-controlled, gestational diabetes (also called gestational diabetes mellitus, or GDM) can raise the risk for a number of issues. These range from high blood pressure during pregnancy, or pre-eclampsia, to having a large baby that can increase the chances of injuries during delivery to the mother or child, making it more likely a cesarean section will be needed. Proper management is key for the health of the pregnancy and to lower the risk of complications.

How to Prevent Gestational Diabetes

The reasons some women develop gestational diabetes aren't fully understood, and there's no way to absolutely ensure it won't occur, yet weight is often a factor. Experts advise taking steps starting when trying to become pregnant to reach a healthy body weight, or to lose weight as needed.

Women who have a body mass index, or BMI, above 30 -- which is considered obese -- are more likely to develop gestational diabetes, says Dr. Athena Philis-Tsimikas, corporate vice president of Scripps Whittier Diabetes Institute in San Diego. Women should talk with their doctors about appropriate weight gain during pregnancy, based on their BMI and following Institute of Medicine guidelines.

Race or ethnicity is another risk factor for gestational diabetes. "We know the Hispanic population [and] African-American and Asian-American [women] have higher risk and can go on to develop it even at somewhat leaner BMIs," Philis-Tsimikas says.

Generally speaking, women who've had a previous pregnancy with gestational diabetes are very likely to develop it again, she says, especially those who are overweight. However, even women who aren't overweight or don't have other clear-cut risk factors can develop gestational diabetes, and experts say there's no perfect way to assess risk.

While weight is an important consideration, clinicians generally advise following best practices -- or advice that would be suggested to anyone to improve overall well-being. That includes eating a proper diet and being physically active starting before pregnancy -- research finds pre-pregnancy fitness is linked with lower gestational diabetes risk -- and during pregnancy.

No matter how often it may be floated by well-meaning friends and family, doctors refute the myth that pregnancy is a nine-month excuse for women to eat whatever they want and to be inactive -- or that doing so won't have a health impact. "Pregnancy is not a free-for-all," says Dr. Kelli Culpepper, an OB-GYN in private practice in Dallas who is affiliated with Medical City Dallas Hospital. In terms of what one eats, that amounts to just adding about 300 to 400 extra calories a day, she says. Culpepper adds that the importance of physical activity during pregnancy is frequently overlooked. "It's OK to be active when you're pregnant," she says. And not only is it all right, it's doctor-recommended (with very limited exceptions that doctors can counsel patients on individually if or when concerns arise). "It's great for you," she says.

[See: How to Cope With Gestational Diabetes.]

Getting Tested for Gestational Diabetes

Because even assessing known risk factors for gestational diabetes misses many who go on to develop it, GDM screening is now essentially universal.

"Virtually everyone is screened unless you have no risk factors for gestational diabetes, and virtually everyone in the United States has some risk factors for diabetes," says Dr. Ellen Seely, director of the clinical research, endocrinology, diabetes and hypertension division at Brigham and Women's Hospital in Boston, and professor of medicine at Harvard Medical School.

Since gestational diabetes usually develops around the 24th week of pregnancy, the CDC notes testing for GDM usually happens between the 24th and 28th weeks. While those at high risk for GDM may be tested earlier, experts say that it's important to be tested after the first trimester, since diabetes detected earlier than that is likely, in fact, to be Type 1 diabetes or Type 2 diabetes.

There's ongoing debate over the best approach to testing: Some experts say performing a single gestational diabetes test is the best way to check for the condition. Most providers in the U.S. currently use a two-test system, which is endorsed by the American College of Obstetricians and Gynecologists.

The first is a glucose screening test, which involves drinking a liquid with glucose, then having blood drawn an hour later to check one's blood sugar level. If it's higher than normal (or exceeding 140 milligrams per deciliter), a follow-up glucose tolerance test is needed. This involves doing a blood test to check blood sugar before and then multiple times after drinking a liquid with glucose. Based on blood-glucose levels (which may vary based on the amount of glucose consumed), a clinician will determine if a patient has GDM. It's typically the case that women don't experience any gestational diabetes symptoms. With other types of diabetes there are outward signs, like you're thirsty or you have to pee a lot, Culpepper notes. "Those things don't happen in gestational diabetes," she says. The lack of outward signs characteristic of GDM is all the more reason experts emphasize the importance of routine screening.

[See: 10 Myths About Diabetes.]

Managing Gestational Diabetes

The prospect of having to manage a new (if temporary) condition when already going through so much with pregnancy can be daunting for women diagnosed with gestational diabetes.

"The first thing is that you need to be measuring your blood sugar very frequently," Philis-Tsimikas says. "This is probably one of the hardest transitions for women that are pregnant -- they're already thinking about so many other things with this pregnancy." But despite the challenges, clinicians say it's critical GDM is well-controlled to reduce complication risk.

New technology, or what's called a flash glucose monitor (the FreeStyle Libre system), is now available to continuously monitor blood sugar levels, as an alternative to frequently pricking a finger to draw blood. It's a small patch sensor that you put on your arm -- "it does have a tiny needle that goes just under the skin -- then you don't have to prick your finger for blood sugars, you just swipe a sensor in front of it," Philis-Tsimikas explains. It stays on for 10 days, before you replace it with another patch sensor.

Whatever approach you take, clinicians remind that there's plenty of reasons to properly control GDM. When it's not well-managed, along with an increased likelihood of developing pre-eclampsia, women have a greater chance of delivering a bigger baby, which can increase the risk for childbirth-related injury to mother and child. Because of the baby's larger size, injuries sometimes occur during vaginal delivery to the baby's shoulder, called shoulder dystocia, involving damage to what's called the brachial plexus, a network of nerves, from the spine that extend down the arm.

Diet is a central component of managing GDM. Along with limiting sugar, that involves keeping careful tabs on what portion of one's diet is carbs, as well as the amount of protein and fat consumed. While specialists who regularly treat patients with diabetes, namely endocrinologists, advise on appropriate diet, experts also extol the benefits of consulting with a registered dietitian to develop a game plan. "I think best practices, you should really have a patient see a registered dietitian," Culpepper says -- something she has patients do to get more specific advice for managing gestational diabetes.

When lifestyle changes and diet alone aren't enough, medication -- most commonly insulin -- is also prescribed to manage gestational diabetes.

Prevention of Type 2 Diabetes After GDM

Since GDM occurs during pregnancy, once the baby arrives, it's easy to put diabetes in the rearview. But though there's certainly no shortage of other things to think about with a newborn at home, experts suggest keeping a prevention mindset going forward.

That's because about 50 percent of women with gestational diabetes will go on to develop Type 2 diabetes, the CDC notes. Fortunately, even as the risk is especially high in this group, clinicians say it's by no stretch inevitable that women with GDM will go on to develop Type 2 diabetes.

"If a woman has had diabetes during pregnancy, the recommendation from most organizations, including the American Diabetes Association, is that she adopt a healthy lifestyle to lose weight and be physically active," Seely says. The goal is, by eating healthy and exercising, to get back to pre-pregnancy weight. "Then if they're obese or overweight, just continue losing weight," she says.

Given the many responsibilities that come with caring for a newborn, making major lifestyle changes to boot can be a tall order. Fortunately, studies show that taking preventive steps helps not only immediately after the pregnancy, but in the years to follow (though experts don't advise waiting to make changes).

Ongoing research on the Diabetes Prevention Program, sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases, has shown that "people who are at high risk for Type 2 diabetes can prevent or delay the disease by losing a modest amount of weight through lifestyle changes (dietary changes and increased physical activity)." Initial research Seely led on a web-based program called Balance After Baby using the DPP approach has also shown promise. "We modified the Diabetes Prevention Program modules and materials to do a completely web-based program where the woman ... can do the entire program without ever having to come to a medical center -- with the goal of helping women lose their pregnancy weight gain at one year after delivery," she says. "And we succeeded in that with the web-based intervention." The focus now is testing a larger population to see if the program might be rolled out nationally. "It's not available yet," Seely says.

[See: The Best and Worst Exercises for Pregnant Women.]

In the meantime, women can participate in the DPP or make lifestyle changes on their own that, experts stress, could ultimately prevent developing Type 2 diabetes, after having had GDM.

Michael Schroeder is a health editor at U.S. News. He covers a wide array of topics ranging from cancer to depression and prevention to overtreatment. He's been reporting on health since 2005. You can follow him on Twitter or email him at mschroeder@usnews.com.