New standards of care expand diagnosis of gestational diabetes

The American Diabetes Association has revised its annual standards of care for the testing of gestational diabetes. Although the new recommendations may double the number of women who are diagnosed with gestational diabetes, it is expected to help mothers and newborns avoid complications associated with diabetes.

The updated recommendations were the result of data from the multinational, epidemiologic Hyperglycemia and Adverse Pregnancy Outcomes (HAPO) study, which highlighted the correlation between maternal glycemia at 24 to 28 weeks gestation and the risk for maternal, fetal and neonatal adverse events. Data also suggest the ranges of maternal glycemia that were previously deemed normal may actually be detrimental to the mother and child. Further, gestational diabetes has typically been defined as any glucose intolerance accompanying the onset of pregnancy. That single criterion, however, ignores a now growing problem.

“As the ongoing epidemic of obesity and diabetes has led to more type 2 diabetes in women of childbearing age, the number of pregnant women with undiagnosed type 2 diabetes has increased. Because of this, it is reasonable to screen women with risk factors for type 2 diabetes at their initial prenatal visit, using standard diagnostic criteria,” according to the association’s annual revision to the Standards of Medical Care.

Changes in screening, diagnosis

Screening for undiagnosed type 2 diabetes at the first prenatal visit is now recommended in women who have risk factors; however, a diagnosis at this stage would be considered a diagnosis of type 2 diabetes and not gestational diabetes.

Women without diabetes should also undergo a 75-g 2-hour oral glucose tolerance test at 24 to 28 weeks gestation, with any one of the following criteria for gestational diabetes: more than 92 mg/dL for the fasting glucose test; more than 180 mg/dL for the 75-g 1-hour OGTT; and more than 153 mg/dL for the 75-g 2-hour OGTT.

To determine whether gestational diabetes is actually a pre-existing case of undiagnosed type 2 diabetes, the revised guidelines emphasize the importance of screening women with gestational diabetes at 6 to 12 weeks after delivery and continued screening for development of diabetes or prediabetes at least every 3 years.

Expanded diagnostic criteria

The broadened recommendations will likely increase the prevalence of gestational diabetes considerably, but the authors said early intervention is vital. Under the current guidelines, about 135,000 US women are diagnosed with gestational diabetes each year, or 4% of all pregnant women. Under the new diagnostic criteria, this figure is expected to double.

“It is important to emphasize that women identified by the newer, but not older, diagnostic criteria will not need the same intensity of intervention, but will likely require only lifestyle management,” Carol Wysham, MD, chair of the ADA Professional Practice Committee and associate clinical professor of medicine at University of Washington School of Medicine, told Endocrine Today. “This will require development of and payment for group education and follow-up of these patients.”

The ADA has officially adopted these recommendations. Wysham said the association realizes that widespread implementation of the guidelines will not happen overnight.

“Health systems need time to convert to the new strategy and, in the interim, can continue to use prior methods for diagnosis until they can make the switch,” Wysham said in a press release. “It’s important that they do ultimately convert though, as the new definition will enable us to ward off preventable complications in both mother and child.” – by Melissa Foster

For more information:

• American Diabetes Association. Diabetes Care. 2011;34:S3-S61.

Disclosure: Dr. Wysham reports no relevant financial disclosures.

Finally, we have consensus on the diagnostic criteria for gestational diabetes and pregnancy complicated by type 1 and type 2 diabetes. The ADA’s Standards of Medical Care for 2011 clearly delineate a simple procedure for the inclusion of all pregnant women in testing for gestational diabetes. Now, we will not have to use the two-step procedure, but rather just a 75-g OGTT that only lasts 2 hours.

Universal testing of all pregnant women will decrease the complications of gestational diabetes for the mother and infant. Although universal testing will double the number of women identified with gestational diabetes from 9% to 18%, the increase does not significantly increase health care costs. Because the primary treatment for gestational diabetes is lifestyle change and the education process is encouraging healthy eating patterns, the impact may result in decreasing the number of persons in the next generation with diabetes.

– Lois Jovanovic, MD
Endocrine Today Editorial Board member

Disclosure: Dr. Jovanovic reports no relevant financial disclosures.

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