Two decades ago caffeine was the subject of controversy. In 1980, the US FDA issued a warning that called upon pregnant women to either reduce or eliminate their consumption of caffeine. Many questions remained, however, and the FDA responded with a series of studies that looked at, among other things, the relationship between caffeine consumption and birth defects.

For most of these studies, average caffeine consumption was considered to be four or more cups per day. Other FDA studies focused on pregnant rats who were given caffeine in their water or through a pipe directly into their stomachs. Of particular concern to the researchers is that caffeine is able to cross the placenta into the infant's circulation. (It is also transferred by mother's breast milk). Throughout the series of FDA studies, caffeine use was not implicated as a cause of birth defects.

This did not, however, lead the FDA to change their stance on this question. As quoted by Chris Lecos, Gary Flamm, of the Office of Toxicological Sciences at FDA's Center for Food Safety and Applied Nutrition, said, "I think it is quite fair to say that our concerns have been diminished quite significantly." However, he went on to say that women should remain cautious about consuming large amounts of caffeine during pregnancy. "We are not prepared to rescind that warning (to pregnant women) because we have not reached the point where we have resolved all of the questions that impact on the issue of safe conditions of use of caffeine." (Source: Caffeine Jitters: Some Safety Questions Remain)