Recent reports on the relationship between caffeine consumption by pregnant women and their infants' risk of miscarriage, low birth weight, preterm delivery and congenital malformations were reviewed. The evidence continues to support the view that moderate consumption of caffeine by pregnant women does not adversely affect their fetuses.
PIP: Reversing the recommendations made by the U.S. Food and Drug Administration of 1981, a review of human epidemiological studies finds no adverse effect of caffeine on pregnancy outcome. Several large studies are discussed on each of the following topics: congenital malformations, miscarriage, low birth weight and preterm delivery. The previous warning was based on gavage feeding of large doses of caffeine to rats, and found a particularly high incidence of facial cleft. Congenital malformations were examined in studies of 12,000 women at Harvard (coffee and tea only), and smaller studies at Boston University, Finland and Tohoku University in Japan (only 0.5% of Japanese women are heavy coffee drinkers, and tea was not considered). A 2nd group of analyses examined low birth weight, at Loma Linda, Harvard, Ottawa, Seattle and elsewhere. Only 1 study, which controlled for nicotine but not education, weight or alcohol, found significantly lower birth weight in 12 women who consumed 300 mg caffeine daily. Preterm birth was not increased in 2 studies. Spontaneous abortion was more likely in 2 studies, the Japanese study with limitations noted above, and the Yale study, which found a higher probability of 2nd trimester miscarriage for both caffeine and alcohol drinkers. These studies apparently prompted the FDA to issue a new statement clearing caffeine, as currently used in foods, of health risk.