Gestational Diabetes: A Risk Factor for Autism?

With commentary by Alycia Halladay, PhD, chief science officer of the Autism Science Foundation

Women who develop gestational diabetes early in their pregnancy have a slightly higher risk of having a child diagnosed with autism, according to a new study published in the Journal of the American Medical Association (JAMA). The large-scale study of more than 322,000 children, found that women diagnosed with diabetes by the 26th week of pregnancy were 42 percent more likely to have a child with autism. The risk is still very small, but significant, rising from a 1 percent risk (in this study) to a 1.4 percent risk.

“Children born to mothers with gestational diabetes are at risk for diabetes themselves, obesity, and through this evidence, autism,” says Alycia Halladay, PhD, chief science officer of the Autism Science Foundation.

gestational diabetes and autism Developing gestational diabetes before week 26 of pregnancy can increase the baby's risk of autism. The study did not find an increased risk of autism for babies born to women who were already diagnosed with diabetes before getting pregnant. This might be in part because women with diabetes who become pregnant have made lifestyle modifications that keep their sugar levels in check and may also be taking medications to control their blood sugar. Similarly, those diagnosed with gestational diabetes after 26 weeks (the third trimester) did not have an increased risk. The study authors speculated that being exposed to untreated high blood sugar during critical brain development early in the pregnancy may have contributed to the autism risk.

“The authors suggest it could be the result of direct damage to the developing brain because of too much glucose or inflammation, which have already been associated with autism,” says Halladay.

Combatting the risk

Taking care to manage gestational diabetes by working closely with your obstetrician and other healthcare providers is crucial. Some important tips:

Get screened. “Pregnant women should take the glucose tolerance test between 24 and 28 weeks of pregnancy, but the earlier the better,” says Halladay. “It’s not going to tell you if you are going to have a child with autism – but it will tell you if you have high blood sugar that can be controlled through medication and diet,” she says.

The American College of Obstetricians and Gynecologists recommends even earlier pregnancy screening for women who are at risk for diabetes, including women who are overweight or obese, who have a family history of diabetes, those with polycystic ovary syndrome (PCOS), or those with a prior history of gestational diabetes or having a prior delivery of a large baby. Certain ethnic groups are at higher risk of gestational diabetes as well, including Latinos, African American, Asian American, Native American and Pacific Islanders.

Repeat testing. If the result of early testing is negative, women at risk should have repeat screening between the 24th and 28th weeks of gestation. In addition, women with gestational diabetes should be tested about six to 12 weeks after their delivery, and should be screened for diabetes throughout their life, says Jane Chiang, MD, pediatric endocrinologist and senior vice president for medical affairs at the American Diabetes Association (ADA).

Modify your diet. “We know that 70 to 80 percent of women with gestational diabetes can be managed with diet and exercise modifications,” says Chiang. Managing gestational diabetes means keeping blood sugar levels from spiking. The ADA recommends that women with gestational diabetes work with a registered dietitian nutritionist (RD/RDN) to develop a personalized nutrition plan. The goal is to eat a high- fiber diet and aim for whole grains, which take longer to digest. “We recommend healthy eating, and we always recommend cutting back on refined sugars, especially from sweetened drinks, and eating a lot of fiber-rich food,” says Chiang.

“You can’t really restrict calories too much when you’re pregnant because women actually need more calories,” says Jane Jeffrie Seley, DNP, MPH, diabetes nurse practitioner and certified diabetes educator, New York Presbyterian-Weill Cornell Medical Center, New York City. She recommends dividing up the amount of calories you eat into three main meals and three snacks.  The time between snacks and meals should be as close to two hours as possible.

Seley advises pregnant women to eat fewer carbohydrates for breakfast. “Early in the morning, because of the pregnancy hormones, women are more insulin resistant, and may have more of a blood sugar spike after breakfast,” she says.

Get exercise. Studies have shown that exercise, particularly weight training, increases muscles mass and can improve the body’s use of insulin, lowering the risk of diabetes. Moderate exercise is recommended for most pregnant women and particularly those with gestational diabetes. Speak to your health care provider first to discuss an exercise plan while pregnant.

Monitor blood sugar levels. If you are diagnosed with gestational diabetes, your diabetes care team will show you how to monitor your blood sugar levels. Blood sugar levels are typically checked at least four times a day—once in the morning, and again about one hour after every meal. Some women may need to check more frequently, while other can check a few times a day. Your health care provider will guide you on how often to test. Testing is typically a finger prick test.

Take medications. Some women can’t control their blood sugar levels through lifestyle modifications and may need to take insulin or other medications that are considered safe during pregnancy. “Pregnant women on insulin need to be monitored closely by their health care provider,” says Chiang.


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