Expectant mothers will want to put those jaunts to Starbucks off for a while (say, nine months?), as a new study emphasizes how drinking caffeine can lead to miscarriage.

The Kaiser Permanente study, published in the American Journal of Obstetrics and Gynecology, found that women who drink a cup and a half of coffee (or other caffeinated beverages like tea or soda) daily during the early stages of their pregnancy are more likely to have a miscarriage than women who abstain.

While pregnant women are often told to avoid or limit their caffeine intake, the Kaiser Permanente study - in which pregnant women were questioned about their caffeine use - is the first to make a strong case about the risk of miscarriage caffeine carries.

"I would probably not even recommend a cup a day, based on this," Dr. Aaron Caughey, a perinatologist at UCSF told The San Francisco Chronicle. "It's not a huge risk, but it's a real effect."

It's important to note that the study only investigated the effects of caffeine on women in the early stages of pregnancy. Of the 1,063 expectant mothers participating in the study, 16% had miscarriages. Researchers found that those who had 200 mg of caffeine a day were twice as likely to miscarry than those who had less than 200 mg or no caffeine at all. The risk remained even when factors like age and smoking habits were considered.

Though the study will undoubtedly make pregnant women lay off, or at least restrict, their caffeine intake, doctors are careful to note that most miscarriages are caused by genetic issues, not the mother's lifestyle.