- To determine the incidence, obstetric risk factors and pregnancy outcome of placental abruption at term. A comparison of all singleton term deliveries (> or = 37 weeks' gestation) complicated with placental abruption to singleton term deliveries without placental abruption. Multivariate analysis was performed to investigate independent risk factors for placental abruption. Placental abruption complicated 0.3% of all term deliveries (n = 72,995). A multiple logistic regression model with backward elimination found the following factors to be independently associated with the occurrence of placental abruption in term pregnancies: pregnancy-induced hypertension (PIH), intrauterine growth restriction (IUGR), non-vertex presentation, hydramnios and advanced maternal age. Perinatal mortality was significantly higher in pregnancies complicated with placental abruption (OR = 30.0, 95% CI 19.7-45.6; p < 0.001). In order to assess whether the increased risk for perinatal mortality was due to the placental abruption or to its significant association with other risk factors, a multivariate analysis was constructed with perinatal mortality as the outcome variable. Placental abruption (OR = 50.5, 95% CI 32.2-79.1), cord prolapse, small for gestational age and congenital malformations were found to be independent risk factors for perinatal mortality. Abruption of the placenta at term was found to be significantly associated with PIH, non-vertex presentation, IUGR, hydramnios and advanced maternal age. Owing to the independent association found between placental abruption and perinatal mortality, these conditions should be carefully evaluated in order to reduce the occurrence of placental abruption.