Issue 170 Item 2 Blood Test Can Predict Diabetes During Pregnancy

A blood test given during the first trimester of pregnancy helps doctors predict which women will develop diabetes later on.

Identifying these "at-risk" women early in pregnancy could give doctors more time to act and lead to better outcomes.

Diabetes during pregnancy, or gestational diabetes mellitus (GDM), affects about 4% of women. GDM can make pregnancy difficult for the mother, but it can also cause problems for the unborn baby. For instance, babies of mothers with GDM are often abnormally large–a problem that makes c-section much more likely.

study author Dr. Ravi Thadhani, from Massachusetts General Hospital in Boston, said that, GDM is now diagnosed in the third trimester with a blood sugar test that requires the patient to fast. Unfortunately, after GDM has been diagnosed, it’s really too late to do anything about it, he added.

If, however, "GDM could be predicted in the first trimester, then there might be time for interventions that would have a beneficial impact," he said.

In the new study, Thadhani’s team measured blood levels of protein called sex hormone binding globulin (SHBG).

"SHBG has been shown to be a good predictor of…diabetes" in people who aren’t pregnant. "So we decided to see if it was also useful during pregnancy," Thadhani explained. Unlike blood sugar testing, SHBG testing does not require fasting and can be performed during the first trimester, he added.

The study involved 44 pregnant women who developed GDM in the third trimester and 94 women who did not. SHBG levels were measured in blood samples that were collected from both groups during the first trimester.

Women who developed GDM had SHBG levels that were much lower than those of women who remained diabetes-free throughout pregnancy. Moreover, the SHBG level remained an important predictor of GDM even after considering other factors typically associated with diabetes.

So how good is the SHBG level at predicting diabetes during pregnancy? That remains to be determined, Thadhani said, adding that the purpose of the current study was simply to show an association between the two. Larger studies are in the works that will help answer this question, he added. American Journal of Obstetrics and Gynecology, July 2003.

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DID YOU KNOW:
The Diabetes Education Society offers online accredited continuing education programs. Got an hour, take a course. Visit www.MedEdOps.org, take the free sample course and review the Course Catalog. Then update yourself and your staff to meet your Education Recognition requirements. For more information call (800) 659-5808.