Low birth weight and preterm births: Etiologic fraction attributable to prenatal drug exposure

Objectives: To determine the factors that would increase the likelihood of outcomes: low birth weight (LBW), preterm births and intrauterine growth restriction (IUGR). Study design: Secondary data analysis from a multi-center study. Risk factors for each outcome were derived from logistic regression models. Odds ratios (OR), 95% confidence intervals, and population-attributable risk proportions (PAR%) were estimated. Results: Prenatal cocaine exposure increased the likelihood of LBW (OR: 3.59), prematurity (OR: 1.25), and IUGR (OR: 2.24). Tobacco, but not marijuana, significantly influenced these outcomes. Alcohol had an effect on LBW and IUGR. Etiologic fractions (PAR%) attributable to tobacco for LBW, prematurity, and IUGR were 5.57, 3.66, and 13.79%, respectively. With additional drug exposure including cocaine, estimated summary PAR% increased to 7.20% (LBW), 5.68% (prematurity), and 17.96% (IUGR). Conclusion: Disease burden for each outcome increases with each added drug exposure; however, etiologic fraction attributable to tobacco is greater than for cocaine.