Cigarette, alcohol, and caffeine consumption: risk factors for spontaneous abortion.
To study the association between cigarette, alcohol, and caffeine consumption and the occurrence of spontaneous abortion. The study population consisted of 330 women with spontaneous abortion and 1168 pregnant women receiving antenatal care. A case-control design was utilized; cases were defined as women with a spontaneous abortion in gestational week 6-16 and controls as women with a live fetus in gestational week 6-16. The variables studied comprise age, parity, occupational situation, cigarette, alcohol, and caffeine consumption. The association between cigarette, alcohol, and caffeine consumption was studied using logistic regression analyzes while controlling for confounding variables. In addition stratified analyzes of the association between caffeine consumption and spontaneous abortion on the basis of cigarette and alcohol consumption were performed. Women who had given birth twice or more previously had increased odds ratio (OR), 1.78 (1.27-2.49), whereas women who were students had decreased OR, 0.55 (0.34-0.91) for having spontaneous abortions. Regarding lifestyle factors, the adjusted ORs among women who consumed 5 units or more alcohol per week or 375 mg or more caffeine per day were 4.84 (2.87-8.16) and 2.21 (1.53-3.18), respectively. Women who smoked 10-19 cigarettes and 20 or more cigarettes per day did not have significantly increased ORs for having spontaneous abortions, after adjusting for other risk factors. Consumption of 5 or more units alcohol per week and 375 mg or more caffeine per day during pregnancy may increase the risk of spontaneous abortion.