Screening for Gestational Diabetes during Pregnancy: Recommendation from the U.S. Preventive Services Task Force

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The summary below is from the full reports titled "Screening for Gestational Diabetes Mellitus: U.S. Preventive Services Task Force Recommendation Statement" and "Screening for Gestational Diabetes Mellitus: A Systematic Review for the U.S. Preventive Services Task Force." They are in the 20 May issue of Annals of Internal Medicine (volume 148, pages 759-765 and pages 766-775). The first report was written by the U.S. Preventive Services Task Force; the second report was written by T.A. Hillier, K.K. Vesco, K.L. Pedula, T.L. Beil, E.P. Whitlock, and D.J. Pettitt.

Who developed these guidelines?

The U.S. Preventive Services Task Force (USPSTF) is a group of health experts that reviews published research and makes recommendations about preventive health care.

What is the problem and what is known about it so far?

When diabetes, or abnormally high blood sugar, occurs during pregnancy, it is called gestational diabetes. Women with gestational diabetes are at risk for complications, such as very large babies, difficult labor and delivery, and stillbirth. Being overweight, being older than 25 years of age, or having family members with diabetes increases a woman's risk for gestational diabetes.

The treatment of gestational diabetes includes special diet and possibly insulin injections. If a pregnant woman developed diabetes symptoms (increased thirst, frequent urination), she should be checked for gestational diabetes. But many women with gestational diabetes have no symptoms, so some doctors do tests to check for it around the 24th week of pregnancy, even if a woman has no symptoms. Testing people without symptoms is called screening.

The USPSTF wanted to find out whether pregnancy outcomes are better for women who are screened for gestational diabetes than for women who are not screened.

How did the USPSTF develop these recommendations?

The authors reviewed published research to measure the benefits and harms of screening pregnant women for gestational diabetes.

What did the authors find?

The USPSTF found that there was not enough information to know whether there are any benefits to screening for gestational diabetes during pregnancy. Treatment of gestational diabetes does reduce a woman's risk for having a very large baby, but there is not enough information to know whether there are other health benefits. The USPSTF found information showing that screening can cause anxiety, but did not find that it causes long-term psychological problems. It also found that most positive screening results are false positive. "False positive" means that, on further testing, the person did not actually have gestational diabetes, so screening may cause unnecessary inconvenience, anxiety, testing, and treatment.

What does the USPSTF suggest that patients and doctors do?

The USPSTF recommends that the choice to screen should depend on how a woman and her doctor weigh the potential benefits (fewer very large babies and uncertain other benefits) and harms (anxiety, false-positive results). Pregnant women should eat a healthy diet and exercise so they do not gain more weight than their doctors recommend.

What are the cautions related to these recommendations?

Recommendations may change as new studies become available.