Gestational Diabetes Underdiagnosed

Panel Calls for Changes That Could Triple Cases of Gestational Diabetes

Reviewed by Louise Chang, MD on February 26, 2010
From the WebMD Archives

Feb. 26, 2010 -- In response to research confirming that even small elevations in blood sugar during pregnancy can lead to sick babies, an international panel of experts is recommending sweeping changes in how gestational diabetes is diagnosed.

If adopted, the changes would mean that in the future two or three times as many pregnant women would be diagnosed and treated for gestational diabetes.

About 5% of pregnant women in the United States receive a diagnosis of gestational diabetes.

But Northwestern University Feinberg School of Medicine Professor of Metabolism and Nutrition Boyd Metzger, MD, says closer to 15% of pregnant women and their babies would benefit from treatment.

“Current recommendations for the diagnosis of gestational diabetes are designed to identify women at risk for developing diabetes after pregnancy,” Metzger tells WebMD. “But we now know that many low-risk women with blood sugar levels considered normal in the past are at risk for having overweight babies.”

High-birth-weight babies have an increased risk for obesity and diabetes later in life, and women carrying large babies are at increased risk for premature delivery and C-section delivery.

Modest Increases in Blood Sugar Are Risky

Findings from a seven-year, international study led by Metzger showed that even modest increases in blood sugar during pregnancy raise the risk for complications to mothers and their babies.

More than 23,000 women who took part in the trial were followed for nearly a decade. The study was published in May 2008.

Several months later, diabetes experts from across the globe met to consider the clinical implications of the findings and this meeting led to the new recommendations.

Under the proposed guidelines, a fasting blood sugar of 92 or higher, a one-hour glucose tolerance test reading of 180 or higher, or a two-hour glucose tolerance test of 153 or higher would meet the criteria for gestational diabetes.

“Any one of these would be enough to make the diagnosis,” Metzger says.

He says that at these levels, the risk of having an overweight baby or developing pregnancy-related high blood pressure doubles and the risk for early delivery increases by 40%.

The consensus panel recommendations appear in the March issue of the American Diabetes Association (ADA) journal Diabetes Care.

But it is not clear if the ADA or the American College of Obstetricians and Gynecologists (ACOG) will endorse the proposed guidelines.

An ACOG spokesperson tells WebMD the group does not comment on recommendations by other organizations.

Carol J. Homko, PhD, of the ADA, says the recommendations may overwhelm already struggling obstetrics practices.

Homko is an associate professor of medicine with a joint appointment in obstetrics and gynecology at Temple University in Philadelphia. She also served on the ADA’s Gestational Diabetes Mellitus workgroup.

“I worry that these practices may not have the resources to suddenly double or triple their gestational diabetes caseload,” she says.

‘Most Women Won’t Need Drugs, Insulin’

Metzger says most women with mild gestational diabetes can be successfully treated with dietary and other lifestyle changes and will not need drugs or insulin.

But Homko points out that even lifestyle modification usually requires close medical supervision to be successful. She says there is also little consensus on the type of diet women with gestational diabetes should follow.

Metzger recommends a diet that balances protein, carbohydrates, and fats and is very low in simple sugars.

Lois Jovanovic, MD, counsels her gestational diabetes patients to eat a very low-carbohydrate diet.

Jovanovic, who is CEO and chief scientific officer of the Sansum Diabetes Research Institute in Los Angeles, supports the new recommendations.

“If we don’t do something, more and more women are going to have big, sick babies and these babies will be the next generation of the type 2 diabetes epidemic,” she tells WebMD.

Show Sources


Metzger, B.E. Diabetes Care, March 2010; vol 33: pp 676-682.

Boyd E. Metzger, MD, Tom D. Spies Professor of Metabolism and Nutrition, Northwestern University Feinberg School of Medicine, Chicago.

Carol J. Homko, PhD, American Diabetes Association Gestational Diabetes Mellitus Workgroup; associate professor of medicine, Temple University School of Medicine, Philadelphia.

Lois Jovanovic, MD, FACE, CEO and Chief Scientific officer, Sansum Diabetes Research Institute; clinical professor of medicine, University of Southern California-Los Angeles Medical Center.

News release, Northwestern University News.

ACOG Practice Bulletin, Gestational Diabetes.

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