A woman’s exposure to caffeine during pregnancy is correlated with spontaneous abortion and low infant birth weight. Other lifestyle choices associated with high caffeine consumption, including drinking alcohol and smoking while pregnant, have been implicated as the actual causes for these birth problems.

In this eight-year Danish study, 18,478 pregnant women visiting a department of obstetrics and gynecology provided information about coffee consumption before and 16 weeks into pregnancy. Coffee consumption was classified as 0, 1-3, 4-7, or 8 or more cups per day. Researchers looked for a possible association between coffee consumption and stillbirth (delivery of a deceased fetus after 28 weeks’ gestation) or infant death in the first year.

Pregnant women who consumed eight or more cups of coffee daily while pregnant (5% of subjects) were three times more likely to experience a stillbirth than women drinking no coffee, before adjusting for smoking and alcohol use. After adjusting for these and other factors, women who drank eight or more cups daily remained 2.2 times more likely to have a stillborn child; women drinking 4-7 cups daily remained 1.4 times more likely. The authors suggest a “threshold effect around four to seven cups per day.”

There was no link observed between coffee consumption and infant death in the first year following birth, after adjusting for other factors. The authors also note that they were unable to investigate the effects of caffeine consumed by these women from other sources, including chocolate, cola, and tea; the subjects were noted to consume little caffeine from these other sources.