Alcohol and risk of spontaneous abortion.

The objective of this study was to assess the association between alcohol drinking before and during pregnancy and the risk of spontaneous abortion using data from a case-control study conducted in Milan, Italy. A total of 462 women (median age 30 years) were admitted for spontaneous abortion (within the 12th week of gestation) to a network of obstetrics departments in the greater Milan area. Of these, 148 (32%) were between the fourth and the eighth week of gestation and 314 (68%) between the ninth and the 12th week. A control group was made up of 814 women (median age 29 years) who gave birth at term (> 37 weeks gestation) to healthy infants (Apgar 5th minute > or = 8, weight > or = 3000 g) on randomly selected days at the same hospitals where cases had been identified. A total of 212 cases (46%) and 355 controls (47%) reported alcohol drinking before conception. Considering non-drinkers as the reference category, the relative risks (RR) of spontaneous abortion were 1.2 [95% confidence interval (CI), 0.9-1.6] and 0.8 (95% CI, 0.6-1.1), respectively, in drinkers of one to seven and more than seven drinks per week before conception. No association emerged between the duration of alcohol drinking and the risk of spontaneous abortion. A total of 166 cases (35.9%) and 263 (32.3%) controls reported any alcohol drinking during the first trimester of pregnancy. The corresponding relative risk was 1.1 (95% CI, 0.9-1.4) and no relationship emerged between the number of drinks per week and the risk of abortion.(ABSTRACT TRUNCATED AT 250 WORDS)