Women who frequently drink sugar-sweetened drinks while pregnant may have a significantly higher risk of developing a condition similar to type II diabetes, according to a recent study conducted by Louisiana State University and Harvard researchers.

The study found that pregnant women who drink five or more servings of sugar-sweetened drinks a week are 22 percent more likely to develop gestational diabetes mellitus, which is one of the most common pregnancy complications, according to Liwei Chen, the lead author and assistant professor of epidemiology at the Louisiana State University School of Public Health.

GDM, which causes glucose intolerance in the mother, disappears after giving birth. But babies born to mothers with the condition have a higher risk of birth injury and are more likely to require a C-section delivery. Later in life, these babies also have a much higher risk of developing obesity, type II diabetes, and glucose intolerance.

One unexpected finding was that the risk increase was associated only with consumption of sugar-sweetened cola drinks, such as Coca-Cola and Pepsi, but not with other soft drinks—including fruit punch, diet, and caffeine-free beverages.

Researchers have proposed several hypotheses to explain why sugar-sweetened cola were most strongly associated with GDM, and one possibility is the potentially harmful effect of the caramel coloring used in these drinks.

The next step, Chen said, would be to pinpoint the biological pathway responsible for the onset of the disease.

Although GDM is a serious condition that “increases both short-term and long-term health risk for the mother and the baby,” Chen said that it has not garnered as much attention from the scientific community as other risk factors during pregnancy.

According to Walter C. Willett, chair of the department of nutrition at the Harvard School of Public Health and one of the paper’s authors, the study draws attention to “an added risk to the mother and the infant that would be better prevented.”

Willett, known as an active proponent of taxing sugared drinks to reduce consumption, said he believes that the study’s conclusions should translate into policy action and lead to greater public awareness, especially since the average American currently drinks 11 servings of sugared beverages every week.

During pregnancy, women are more motivated to make lifestyle changes, Willett said. As a result, obstetricians should consider emphasizing the dangers of sugared beverage consumption to their pregnant patients, who are more likely to heed the advice.

The results of the study, which was funded by the National Institutes of Health and used data from the Nurses’ Health Study II, were published in the December issue of “Diabetes Care.”

—Staff Writer Helen X. Yang can be reached at hxyang@fas.harvard.edu.