Substance abuse during pregnancy is one of the most important problems in maternal and neonatal health. Being familiar with the risk of poor pregnancy outcome in these individuals may help them to reduce that risk.

The purpose of the present study is to evaluate the effects on Pregnancy outcome of substance abuse during pregnancy.

The study was conducted as a historical cohort study between two groups of pregnant women with or without substance abuse. Both groups were Iranian housewives, with the same socio economical status, singleton and without any known medical systemic disorder.

1268 women were evaluated in total. 317 women were drug abusers and 951 women were not. The woman in both groups had no significant differences according to neonates’ gender, gestational age, pregnancy-induced hypertension, intra uterine fetal death (IUFD), and ruptured membranes. Maternal age (P = 0.000), maternal weight (P = 0.000), neonatal weight (P = 0.000) were found to be lower in drug abusers. History of previous abortion (p = 0.000) and gravidity (P = 0.000) were higher in drug abusers. Also cesarean delivery [(P = 0.049, RR=1.1 (1.02–1.12)], placental abruption [(P = 0.000, RR=2.7 (1.8–4.1)], meconium passage [P = 0.000, RR=2.6 (2.3–2.8)], neonatal weight of less than 2500 gram [P = 0.000, RR=1.9 (1.8–2)], Apgar score of less than 7 in minute 5 [P = 0.001, RR=1.7 (1.5–1.7)], NICU admission [P = 0.000, RR=3.7 (3.5–3.8)] and neonatal death [P = 0.009, RR= 2.1 (1.8–2.5)] were all higher in drug abusers.

Substance abuse causes poor outcomes in pregnancy, and with control, patients may improve these poor conditions.