Risk Factors for Postpartum Hemorrhage in Vaginal Deliveries in a Latin-American Population

Abstract

To identify risk factors for immediate postpartum hemorrhage after vaginal delivery in a South American population. This was a prospective cohort study including all vaginal births (N=11,323) between October and December 2003 and October and December 2005 from 24 maternity units in two South American countries (Argentina and Uruguay). Blood loss was measured in all births using a calibrated receptacle. Moderate postpartum hemorrhage and severe postpartum hemorrhage were defined as blood loss of at least 500 mL and at least 1,000 mL, respectively. Moderate and severe postpartum hemorrhage occurred in 10.8% and 1.9% of deliveries, respectively. The risk factors more strongly associated and the incidence of moderate postpartum hemorrhage in women with each of these factors were: retained placenta (33.3%) (adjusted odds ratio [OR] 6.02, 95% confidence interval [CI] 3.50-10.36), multiple pregnancy (20.9%) (adjusted OR 4.67, CI 2.41-9.05), macrosomia (18.6%) (adjusted OR 2.36, CI 1.93-2.88), episiotomy (16.2%) (adjusted OR 1.70, CI 1.15-2.50), and need for perineal suture (15.0%) (adjusted OR 1.66, CI 1.11-2.49). Active management of the third stage of labor, multiparity, and low birth weight were found to be protective factors. Severe postpartum hemorrhage was associated with retained placenta (17.1%) (adjusted OR 16.04, CI 7.15-35.99), multiple pregnancy (4.7%) (adjusted OR 4.34, CI 1.46-12.87), macrosomia (4.9%) (adjusted OR 3.48, CI 2.27-5.36), induced labor (3.5%) (adjusted OR 2.00, CI 1.30-3.09), and need for perineal suture (2.5%) (adjusted OR 2.50, CI 1.87-3.36). Many of the risk factors for immediate postpartum hemorrhage in this South American population are related to complications of the second and third stage of labor. II.