Study Urges Treatment for Even Mild Gestational Diabetes

WEDNESDAY Sept. 30, 2009 -- Pregnant women who receive treatment for the mildest forms of gestational diabetes -- including diet and exercise intervention, self-monitoring of blood glucose levels and possibly insulin therapy -- are less likely to have serious birth complications or develop preeclampsia or high blood pressure during pregnancy, according to new research.

It's been unclear whether treating borderline cases of gestational diabetes would make a difference in pregnancy outcomes. But the study's lead author, Dr. Mark Landon, professor and interim chair of obstetrics and gynecology at Ohio State University Medical Center, said that the finding "demonstrates that there's a significant clinical benefit to treating even the mildest form of gestational diabetes."

Results of the study are published in the Oct. 1 issue of the New England Journal of Medicine.

"Now, we have two randomized, controlled trials, and both showed decreases in big babies, preeclampsia and maternal weight gain," said Dr. David Sacks, a maternal-fetal medicine specialist at Kaiser Foundation Hospital in Bellflower, Calif., and the author of an accompanying editorial in the same issue of the journal. The second study he referred to was done in Australia and published in 2005.

Gestational diabetes is a transient form of diabetes that occurs during pregnancy. However, women who've had gestational diabetes have been shown to have a higher risk for developing type 2 diabetes later in life. Depending on the criteria used to define gestational diabetes, the condition occurs in between 1 percent and 14 percent of all pregnancies, according to Landon's study.

"The frequency of gestational diabetes is increasing worldwide, and while most obstetricians screen for this condition, some have remained skeptical about treating mild gestational diabetes, and are not as aggressive in treating milder forms with dietary intervention and self-blood glucose monitoring," Landon explained.

To get a better idea of whether treating women with mild forms of gestational diabetes could make a difference, he and his colleagues recruited 958 pregnant women who were classified as having mild gestational diabetes.

A treatment group of 485 of the women were given counseling on diet and exercise, taught how to monitor their own blood sugar levels and given insulin when necessary. The other 473, considered the control group, received standard pregnancy care. Only 7 percent of the women in the treatment group required insulin, Landon said.

The study found that the frequency of babies born too-large for their gestational age was reduced by more than half -- 14.5 percent of the control group versus 7.1 percent of the treatment group had big babies. The pregnancy complication known as shoulder dystocia, which means that the shoulders have gotten so large they're difficult to deliver, was found to be 4 percent in the control group and 1.5 percent in treated group.

Cesarean delivery rates also were lower for women who received treatment for their gestational diabetes -- 26.9 percent compared with 33.8 percent of the control group. Women who received treatment also had lower rates of preeclampsia and high blood pressure -- 8.6 percent versus 13.6 percent in the control group, the study found.

Landon said that the reduction of many of the birth complications resulted from the mother's blood sugar being under control, which doesn't cause overnourishment of the baby and thus the baby's size stays closer to normal.

Neither Landon nor Sacks could explain the reduction in preeclampsia and high blood pressure. Sacks theorized that because both diabetes and high blood pressure are inflammatory processes, what helps reduce one might also help the other. But, he added, no one really knows right now.

What is clear, said Dr. Miriam Greene, an obstetrician and gynecologist at NYU Langone Medical Center, is that "when women with mild gestational diabetes are treated well, there's a decreased incidence of birth trauma." Greene said that she's already been treating women with the mildest forms of gestational diabetes, and that it does make a difference.

Sue McLaughlin, president of health care and education for the American Diabetes Association, said that the study provides "another example of how preventive health care pays off in positive health outcomes and may save lives, dollars in the health-care system and improve the quality of life in future years for these families."

According to McLaughlin, "Physicians need to take a proactive role in educating women of childbearing age about their risk for this condition so that women can implement healthy lifestyle behaviors, which promote weight control and prevention of excessive weight gain in this and future pregnancies."

More information

The American Diabetes Association has more on gestational diabetes.

Posted: September 2009


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