Gestational Diabetes

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Gestational diabetes, or diabetes that occurs in the second and third trimester of pregnancy and resolves at birth, occurs in approximately 9.2 percent of pregnancies in America. Risk factors for developing gestational diabetes include:

  • A family history of diabetes
  • Being overweight
  • Having had gestational diabetes in a previous pregnancy
  • Having prediabetes
  • Having given birth previously to a child weighing nine pounds or more
  • Having polycystic ovarian syndrome (PCOS)
  • In addition, the same populations at risk for type 2 diabetes—Latino Americans, African Americans, Pacific Islanders, and Asian Americans—are also at greater risk for gestational diabetes.

You will probably be tested for gestational diabetes between weeks twenty-four and twenty-eight of your pregnancy, using an oral glucose tolerance test to see how well your body responds to ingesting a large amount of glucose. If you have a higher risk of gestational diabetes, your doctor may test you earlier, at your first visit during your pregnancy.

Complications of Gestational Diabetes

Women who develop gestational diabetes have problems metabolizing glucose. Their pancreas produces plenty of insulin (the hormone responsible for “unlocking” cells so that glucose can enter them and provide energy), but a condition known as insulin resistance prevents them from using it effectively. When insulin doesn’t work properly, blood glucose (or blood sugar) builds up in the bloodstream, and gestational diabetes is the result.

The fetus of a woman with gestational diabetes may become large for date as it stores the excess glucose it is receiving from the mother as fat, a condition known as macrosomia. A large infant may have a more difficult time descending the birth canal. Other potential risks for the baby include hypoglycemia (low blood sugar) and jaundice. A pediatrician or a neonatolgist, a physician who specializes in high-risk infant care, is often present at the births of gestational-diabetes babies to handle any potential complications.

Women who are able to effectively manage their gestational diabetes and keep blood glucose levels in the safe range dramatically reduce the risk of pregnancy complications. Potential pregnancy complications of uncontrolled gestational diabetes include:

  • Hypertension. High blood glucose levels can cause high blood pressure; hypertension in pregnancy can lead to a dangerous complication known as preeclampsia.
  • Preeclampsia. If high blood pressure becomes severe, preeclampsia may develop. Other signs of preeclampsia include protein in the urine and severe edema (swelling). The only treatment for preeclampsia is delivery of the baby, which may mean a premature birth.
  • Increased risk for developing gestational diabetes in subsequent pregnancies, and type 2 diabetes in the future.

Treatment and Prevention

Gestational diabetes requires treatment with dietary changes, exercise, and/or insulin injections to keep maternal blood glucose levels as close to normal as possible, and to prevent complications in both mother and baby. Women with gestational diabetes are also encouraged to self-test their blood glucose levels often.

There’s no surefire way to ensure the prevention of gestational diabetes, but preconception planning may help to facilitate prevention by reducing some of the risk factors associated with gestational diabetes, such as excess weight.

Strategies known to improve insulin resistance, and that may make a difference in the development of gestational diabetes, include:

  • Maintaining a healthy weight
  • Staying active
  • Eating right

If you’re planning a pregnancy, talk to your doctor about your gestational diabetes risk and how to lower it.

Gestational Testing Goals

If you have gestational diabetes, regular blood sugar checks are important to the health of you and your baby. Talk to your doctor about your specific target goals for testing and how to reach them. The American Diabetes Association’s general guidelines for blood sugar checks are:

  • Before a meal (preprandial/fasting blood glucose level—lower than 95 mg/dl (5.27 mmol/L)
  • One hour after a meal (postprandial/lower than 140 mg/dL (7.77 mmol/L)
  • Two hours after a meal (postprandial/lower than 120 mg/dL (6.66 mmol/L)

Updated by Julia Telfer, MPH, 10/16.


American Diabetes Association. “How to Treat Gestational Diabetes.” June 7, 2013. Last updated April 29, 2014.

American Diabetes Association. “Standards of Medical Care in Diabetes—2016.” Diabetes Care. January 2016. Volume 39, Supplement 1: S1-S112.

DeSisto, C. L., S. Y. Kim, and A. J. Sharma. “Prevalence Estimates of Gestational Diabetes Mellitus in the United States, Pregnancy Risk Assessment Monitoring System (PRAMS), 2007-2010.” Preventing Chronic Disease. Centers for Disease Control and Prevention. June 19, 2014.

U.S. Department of Health and Human Services. “Gestational Diabetes.” National Institute of Diabetes and Digestive and Kidney Diseases. September 2014. Accessed September 18, 2016.