RATE OF CAFFEINE METABOLISM AND RISK OF SPONTANEOUS-ABORTION

In a case-control study of 73 women with and 141 women without spontan eous abortion, the authors determined the activity of the three princi pal caffeine-metabolizing enzymes-cytochrome P-4501A2 (CYP1A2), xanthi ne oxidase, and N-acetyltransferase 2-by measuring levels of caffeine metabolites in urine. After examining the effect of enzyme activity an d different levels of caffeine intake, they concluded that there was n o evidence that an interaction between enzyme activity and caffeine in take during pregnancy resulted in risk of spontaneous abortion. In a s ubsample comparing 24 cases with recurrent (two or more) spontaneous a bortions and 21 controls with two or more livebirths and no previous s pontaneous abortions, the unadjusted odds ratio for low CYP1A2 enzyme activity (below the median) was 0.92 (95% confidence interval (Cl) 0.2 8-3.04) compared with higher CYP1A2 activity. The odds ratio for risk of recurrent spontaneous abortion and low xanthine oxidase activity (b elow the median) versus higher activity was 0.37 (95% Cl 0.10-1.29), P henotypically slow acetylators (N-acetyltransferase 2 index <0.37) had an odds ratio of 1.58 (95% Cl 0.48-5.13) for recurrent loss compared with rapid acetylators. Thus, some association of the latter two caffe ine-metabolizing enzymes with recurrent spontaneous abortion is sugges ted but may also be due to chance.