A case-control study of cocaine use in pregnancy

OBJECTIVE: This study analyzed the relationships between cocaine use, various other parameters, and perinatal outcomes. STUDY DESIGN: A case-control study of cocaine use was conducted among pregnant women delivered at a large urban hospital in New Orleans, Louisiana. Two control patients for each case, matched for age, race, parity, and month of delivery, were selected. RESULTS: Between April and September 1990, there were 2332 admissions to the obstetric service; urine toxicology screens were obtained on 2225 patients. Cocaine metabolites were identified in 166 patients; 138 of these women had data that could be evaluated. These data were compared with those of 276 control patients, and the findings were analyzed. Complications that occurred significantly more often in study patients included vaginal bleeding, abruptio placentae, premature rupture of the membranes, meconium staining of the amniotic fluid, and low birth weight. Study patients were found to use prenatal care less often (45.0% vs 86.4%) and to smoke cigarettes more often (67.4% vs 35.1%). Regression analysis identified lack of prenatal care and smoking as important variables in birth weight. When these two variables were excluded, identifiable differences in birth weight between cocaine and control mothers were no longer present. CONCLUSION: The reduction in birth weight experienced by patients who used cocaine may be explained by lack of prenatal care and by smoking. Other identified differences observed between study and control patients were not significantly altered by smoking or prenatal care.