High Blood Sugar Tied to Pregnancy Complications

The odds of these complications changed continuously as blood sugar levels rose. For example, a woman with the highest levels of blood sugar (but not diabetes) had large babies 26 percent of the time, compared to just 5 percent for women with the lowest blood sugar levels.

"Basically, what they found out is that there is no threshold where you know to treat. That makes it difficult to know what to do with these findings," said Dr. Joel Zonszein, director of the Clinical Diabetes Center at Montefiore Medical Center in New York City.

A second study in the same issue of the journal looked at the use of the oral diabetes medication metformin, versus insulin, the standard treatment for gestational diabetes. The study included 751 women, randomly assigned to receive metformin or insulin treatment.

The researchers found that metformin was well-tolerated, although almost 43 percent of the women eventually required the use of supplemental insulin. There were no serious adverse events reported for mother or baby from the use of metformin, according to the study.

Of this study, Zonszein said, "My guess is that until we have larger studies, there's not going to be a big change in recommendations, because we have so much experience with insulin." But, he added, many women and obstetricians may welcome these findings because "giving a pill is easier than giving insulin." He said another oral medication, glyburide, was also found effective in another small trial.

More information

To learn more about gestational diabetes, visit the American Diabetes Association.

SOURCES: Boyd Metzger, M.D., Tom D. Spies Professor of Metabolism and Nutrition, Feinberg School of Medicine, Northwestern University, Chicago; Don Coustan, M.D., professor and chair, department of obstetrics/gynecology, Warren Alpert Medical School of Brown University, and chief of obstetrics and gynecology, Women & Infants Hospital of Rhode Island, Providence; Joel Zonszein, M.D., director, Clinical Diabetes Center, Montefiore Medical Center, and professor of clinical medicine, Albert Einstein College of Medicine, New York City; May 8, 2008,New England Journal of Medicine