Study suggests link between blood-sugar and birth defects

BOSTON According to a new study, lower blood-sugar levels than originally thought in pregnancy increase the chances of such problems as high-birth-weight babies and increase the need for Caesarean sections, as reported by The Wall Street Journal.

But study authors stopped short of recommending insulin or other treatments for pregnant women with moderately elevated blood-glucose levels. They said further study was needed to decide what level of blood sugar might dictate medication.

The study involved 23,000 women in nine countries. Nearly all had blood-sugar levels below the threshold for gestational diabetes, a condition that usually starts in pregnancy and resolves itself after birth. Gestational diabetes affects about 4 percent of pregnant women, with about 135,000 cases in the U.S. each year, according to the American Diabetes Association.

Untreated gestational diabetes can give babies high blood-glucose levels and lead to excessive birth weight, or macrosomia, a condition that can lead to health problems, including damage to a baby’s shoulders during birth and, later, obesity and diabetes.

The study found that the odds of having a baby with a high birth weight—that is, one higher than 90 percent of all births—rose consistently along with the level of blood sugar. So did the chances of having a first-time C-section.

But based on the study’s findings, researchers couldn’t determine a level at which it made sense to start treatment, such as insulin injections, says Donald Coustan, chair of obstetrics and gynecology at Brown Alpert Medical School. Coustan said the implications of the study are “about the future, not about the present” adding it won’t “affect clinical practice this week or this month.”

Researchers are scheduled to meet next month to discuss the data to determine whether doctors may one day have to treat women whose blood-sugar levels do not meet the current definition of gestational diabetes.