The associations of maternal caffeine consumption and nausea with spontaneous abortion

To examine whether maternal caffeine consumption is associated with the risk of spontaneous abortion, we analyzed data from a population-based prospective study. The study population comprised 575 women delivering singleton livebirths and 75 women who had spontaneous abortions. The subjects were predominantly white, middle-class women enrolled before pregnancy. Study participants were traced to delivery of a liveborn, singleton infant or a spontaneous abortion. Of the 71 women who did not experience nausea, 29.6% had a spontaneous abortion, compared with 7.2% of 514 women who did experience nausea. Maternal caffeine consumption before pregnancy, or in women without nausea, did not increase the risk of spontaneous abortion, whereas maternal caffeine: consumption during the first trimester after nausea started might increase risk of spontaneous abortion (risk ratio = 5.4, 95% confidence interval = 2.0-14.6 for caffeine consumption greater than or equal to 300 mg per day compared with <20 mg per day). These results suggest that maternal caffeine consumption during pregnancy may influence fetal viability in women with nausea.