- The study was aimed to identify risk factors and to elucidate pregnancy outcome following precipitate labor, i.e. expulsion of the fetus within less than 3 h of commencement of contractions. A comparison of patients with and without precipitate labor, delivered during the years 1988-2002, was conducted. Patients who underwent cesarean deliveries were excluded from the analysis. A multiple logistic regression model, with backward elimination, was performed to investigate independent risk factors for precipitate labor. The number of vaginal deliveries that occurred during the study period was 137,171. Of these, 99 were precipitate. Independent risk factors for precipitate labor, using a backward, stepwise multivariate analysis were: placental abruption (odds ratio (OR) = 30.9, 95% confidence interval (CI) 15.9-60.4, P < 0.001); fertility treatments (OR = 3.9, 95% CI 1.7-9.0, P = 0.002); chronic hypertension (OR = 3.1, 95% CI 1.2-7.8, P = 0.015); intrauterine growth restriction (IUGR) (OR = 2.9, 95% CI 1.2-6.8, P = 0.014); prostaglandin E2 induction (OR = 1.9, 95% CI 1.1-3.5, P = 0.045); birth weight < 2,500 g (OR = 1.8, 95% CI 1.1-3.1, P = 0.020); and nulliparity (OR = 1.7, 95% CI 1.1-2.6, P = 0.014). No significant differences were noted between the groups regarding perinatal complications such as meconium stained amniotic fluid, perinatal mortality and low Apgar scores. However, there were higher rates of maternal complications in the precipitate labor group such as cervical tears and grade 3 perineal tears (18.2% versus 0.3%, P < 0.001; and 2.0% versus 0.1%, P < 0.001, respectively), post-partum hemorrhage (13.1% versus 0.4%, P < 0.001); retained placenta (2.0% versus 0.5%, P = 0.02); the need for revision of uterine cavity and packed-cells transfusions (34.3% versus 4.9%, P < 0.001; and 11.1% versus 1.1%, P < 0.001, respectively) and prolonged hospitalization (27.6% versus 19.2%, P = 0.035) as compared to the controls. Precipitate labor is associated with higher rates of maternal complications.