The recommendations about caffeine intake and pregnancy have always been fuzzy. Ask two obstetricians in the same practice and you are likely to get different answers from both. This is partially due to the fact that professional groups like the American College of Obstetricians and Gynecologists and the American Society for Reproductive Medicine have no official stance on the combination of pregnancy and caffeine.
However, a recent study determined that pregnant women and even women trying to conceive should limit their caffeine intake to 200 mg a day, especially in the first four months of pregnancy. (Not sure how much caffeine is in your favorite beverage? Check out Caffeinated Quiz and test your knowledge) The study was based on interviews about caffeine intake in 1063 pregnant women, but not all obstetricians are buying it. The reasons for miscarriages are difficult to explain, but many involve chromosomal abnormalities and there is no proof that caffeine would cause these types of issues.
I, for one, was so sick in my early pregnancies that caffeine in any form was unpalatable. To play it safe, many doctors recommend reducing caffeine intake or avoiding it altogether.
If you are pregnant, first let me say congratulations! Secondly, if you are a caffeine junkie you should talk to your doctor about the matter and maybe just switch to decaf for the next nine months.