Add diet soda to the list of things to avoid while pregnant


There are so many things you’re not supposed to eat or drink when you’re pregnant -- sushi, Caesar salad, blue cheese, lox, coffee and, of course, alcohol. Now researchers have added a new item to that list -- diet soda.

It seems that regular consumption of carbonated beverages made with artificial sweeteners significantly increases the risk of preterm delivery (defined as giving birth after fewer than 37 weeks of pregnancy). Women who drank at least one diet soda per day were 38% more likely to have their baby early compared to women who abstained. For women who drank at least four diet sodas each day, the increased risk was 78%, according to a study published in the September issue of the American Journal of Clinical Nutrition.

These risks were calculated based on data from 59,334 pregnancies that were tracked in Denmark between 1996 and 2002. Women in the study were asked to complete a food frequency questionnaire about halfway through their pregnancies. The timing of their births was recorded in the Danish Civil Registration System.

About one out of every eight babies is born preterm, according to the March of Dimes. “Babies who are born preterm are at higher risk of needing hospitalization, having long-term health problems and of dying than babies born at the right time,” according to the group’s website.

The researchers found no link between consumption of sugar-sweetened beverages and risk of preterm delivery, suggesting that some component of artificial sweeteners is to blame. Noncarbonated diet drinks also weren’t associated with an increased risk of preterm delivery, probably because those drinks contained much lower levels of artificial sweeteners (only about one-half to one-third as much aspartame and acesulfame-K as in carbonated diet drinks, according to the study).

For the sake of comparison, using the same dataset the researchers calculated that women who smoked every day were 21% more likely than nonsmokers to deliver their babies early.

-- Karen Kaplan