Don't smoke, don't drink. Do eat chocolate.

Gregory Nemec

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Mothers-to-be, indulge: chocolate, in moderation, could assure you a safer pregnancy. A team of Yale researchers demonstrated that chocolate consumption during pregnancy is associated with a lower incidence of preeclampsia, a disorder of pregnancy characterized by high blood pressure and protein in the urine. The condition can threaten the health—and even survival—of both the mother and her child. "Preeclampsia in pregnancy is one of the top causes of maternal mortality in the world," says Elizabeth Triche, a research scientist in the School of Epidemiology and Public Health and the study's lead author. "There's evidence in the literature that chocolate can benefit cardiovascular health, and preeclampsia shares a lot of characteristics with cardiovascular disease."

As part of a larger study on prenatal nutrition, the researchers analyzed the chocolate consumption of more than 2,000 women, who were asked to report how much chocolate they ate during the first and third trimesters of their pregnancies. After the women gave birth, Triche's team measured the level of theobromine, a metabolite of chocolate, in each child's umbilical cord blood. (Higher levels indicate higher levels of chocolate consumption.)

Women who had the highest levels of theobromine were significantly less likely to develop preeclampsia than women with the lowest levels, the team reported in the May issue of Epidemiology. This suggests that chocolate does indeed have a protective effect. But no one is sure why.

"There are over 600 plant chemicals in chocolate," Triche says. The flavonoids, magnesium, and theobromine present in chocolate are all known to spur dilation of the body's blood vessels. Any of the three ingredients (or some combination of them) could be responsible for preventing preeclampsia.

Triche recommends that expectant moms refrain from eating chocolate by the bucketful, which could cause too much weight gain or other problems during pregnancy. The women in the study benefited from relatively small amounts, she says. Exactly how much chocolate is guilt-free? "Maybe a candy bar a day."