Potentially bad news for knocked-up Starbucks babes: A study published today suggests that women who consume more than 200 milligrams of caffeine a day double their risk of miscarriage in the first three months of pregnancy. (To put "200 milligrams" in perspective, a "tall" regular coffee from the 'Bux has 260 mg alone.) Researchers writing in the American Journal Of Obstetrics and Gynecology surmise that caffeine can have a negative effect on a developing embryo by restricting blood flow to the placenta or by interfering with the normal function of developing cells. (It can be difficult for a fetus or embryo to metabolize the stimulant.) But! Researchers in the journal Epidemiology aren't entirely convinced.

"I am not persuaded [caffeine] poses a health hazard," says epidemiologist David Savitz, who, Newsweek reports, considers caffeine "among the long list of things you should think about." "We don't really know the truth." And Dr. Alan Peaceman, professor of obstetrics and gynecology at Northwestern University cautions against "creating hysteria": "I tell women not to be guilty about a cup of coffee if that's what they really need. There are a lot of people who are hooked on caffeine, including myself. there is so much guilt out there that women have to deal with when they have a bad outcome in pregnancy. The vast majority is not within their control."

Caffeine Doubles Miscarriage Risk, Study Finds [Reuters]
Cup Of Contradictions [Newsweek]
New Kaiser Permanente Study Fortifies Caffeine's Link To Miscarriage [Eureka Alert]

Related: Starbucks Beverages [Starbucks]