Treating Mild Gestational Diabetes Reduces Birth Complications

Treating pregnant women who have even the mildest form of gestational diabetes can reduce the risk of problems among both infants and mothers, according to a new study.

Gestational diabetes is diabetes that arises for the first time during pregnancy. It affects from 1 to 14% of all U.S. pregnancies. Although it usually goes away soon after the baby is born, it leaves the mother with a higher risk for developing diabetes later in life. Uncontrolled, gestational diabetes can lead to high blood pressure and make it more likely the baby will be large and have a difficult delivery. The baby could also be born with low blood glucose and breathing or other problems.

Treatment is routinely prescribed to all affected women to normalize the elevated blood sugar levels typical of diabetes. In most cases, treatment consists of a specific diet and exercise. If these fail to keep blood sugar in check, medications may be prescribed as well. But while treatment is known to benefit mothers and infants with severe gestational diabetes, until now there was no evidence to show whether treating the mild form of the condition helps, or poses risks for, mothers or their infants.

Led by Dr. Mark Landon of Ohio State University, researchers in the Maternal Fetal Medicine Units Network of NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) set out to investigate. Supported by NICHD and NIH's National Center for Research Resources (NCRR), the scientists enrolled 958 women with mild gestational diabetes. Roughly half the women received nutritional counseling and diet therapy. They also were taught to monitor their blood glucose and given insulin therapy, if necessary. The other half received standard pregnancy care.

In the October 1, 2009, edition of the New England Journal of Medicine, the researchers reported that the women who received treatment fared better than their untreated counterparts. Compared to untreated women, women treated for mild gestational diabetes were half as likely to have an unusually large baby. Their babies were half as likely to experience shoulder dystocia, an emergency condition in which the baby's shoulder becomes lodged inside the mother's body during birth. Treated mothers were also four-fifths as likely to undergo cesarean delivery and three-fifths as likely to develop high blood pressure during pregnancy or to develop preeclampsia, a life-threatening complication of pregnancy that can lead to maternal seizures and death.

“The study results show conclusively that both mothers and infants do better when gestational diabetes is controlled,” says study coauthor Dr. Catherine Y. Spong, chief of NICHD's Pregnancy and Perinatology Branch.

Previous studies suggest that the higher birthweights and greater proportion of body fat seen in the newborns of women with gestational diabetes also pose increased health risks for these children later in life. They are more likely than other children to be overweight and, as adults, more likely to have impaired glucose tolerance, a prediabetic condition.

“The children would need to be followed long term to be certain, but it's possible that treating women with mild gestational diabetes to reduce birthweight and body fat among their newborns may benefit these children later in life,” Spong says.