Background: Animal studies demonstrate teratogenic effects of caffeine, whereas human studies are inconclusive.
Methods: Associations between maternal caffeine consumption and neural tube defects (NTDs) by type of NTD (anencephaly, spina bifida, or encephalocele) were examined using data from the National Birth Defects Prevention Study (NBDPS). Total average daily caffeine from coffee, tea, soda, and chocolate consumption during the year before pregnancy was estimated for 768 mothers of infants with NTDs and 4143 mothers of infants without birth defects who gave birth during 1997 through 2002. Periconceptional use of caffeine-containing medications was evaluated separately. Adjusted odds ratios (OR) and 95% confidence intervals (CI) associated with consumption of total caffeine and each caffeine source were estimated from logistic regression models.
Results: Positive associations were observed between spina bifida and total caffeine consumption (OR 1.4; 95% CI: 1.1-1.9) and each caffeine source except caffeinated tea, which showed a negative association with spina bifida (OR 0.7; 95% CI: 0.6-0.9). Associations with modestly increased risk of NTDs and encephalocele were also observed. The association between caffeine consumption and anencephaly differed by maternal race/ethnicity. No dose effects were found.
Conclusions: Additional studies should confirm whether women who consume caffeine are at increased risk for pregnancies complicated by NTDs.