Cocaine and tobacco use and the risk of spontaneous abortion

Background Cigarette smoking and cocaine use may be risk factors for sponta neous abortion, but data supporting such a link are limited. Methods We studied the associations between cocaine and tobacco use and spo ntaneous abortion among pregnant adolescents and women (age range, 14 to 40 years) who sought care at an inner-city emergency department. A total of 4 00 adolescents and women had spontaneous abortions either at study entry or during follow-up (which lasted until 22 weeks' gestation), and 570 adolesc ents and women remained pregnant past 22 weeks' gestation. Cocaine use was measured at base line by self-reports and analysis of urine and hair sample s, Cigarette smoking was measured by self-reports and urine analysis. Results The adolescents and women in both groups were predominantly black a nd of lower socioeconomic status. Among those who had spontaneous abortions , 28.9 percent used cocaine on the basis of hair analysis and 34.6 percent smoked on the basis of a urine cotinine assay, as compared with 20.5 percen t and 21.8 percent, respectively, of the adolescents and women who did not have spontaneous abortions. The presence of cocaine in hair samples was ind ependently associated with an increase in the occurrence of spontaneous abo rtion (odds ratio, 1.4; 95 percent confidence interval, 1.0 to 2.1) after a djustment for demographic and drug-use variables. However, the use of cocai ne as measured by self-reports and by urine analysis was not. The presence of cotinine in urine was also independently associated with an increased ri sk of spontaneous abortion (odds ratio, 1.8; 95 percent confidence interval , 1.3 to 2.6). Twenty-four percent of the risk of spontaneous abortion coul d be related to cocaine or tobacco use. Conclusions Cocaine use and tobacco use were common in our study population and were associated with a significant risk of spontaneous abortion, (N En gl J Med 1999;340:333-9.) (C) 1999, Massachusetts Medical Society.