Aside from alcohol, which is definitely not OK, caffeine is the most hotly debated drink during pregnancy. Until very recently, about 300 milligrams a day of caffeine were seen as being safe for baby-that's the equivalent of about three cups of coffee or five cans of soda. But a recent study found that pregnant women who had just 200 milligrams of caffeine were twice as likely to miscarry as women who didn't consume caffeine. While this knowledge advises caution, most doctors still believe that controlled amounts of caffeine are probably safe with baby on board.