Postpartum hemorrhage resulting from uterine atony after vaginal delivery: factors associated with severity.

OBJECTIVE To identify factors associated with severity of postpartum hemorrhage among characteristics of women and their delivery, the components of initial postpartum hemorrhage management, and the organizational characteristics of maternity units. METHODS This population-based cohort study included women with postpartum hemorrhage due to uterine atony after vaginal delivery in 106 French hospitals between December 2004 and November 2006 (N=4,550). Severe postpartum hemorrhage was defined by a peripartum change in hemoglobin of 4 g/dL or more. A multivariable logistic model was used to identify factors independently associated with postpartum hemorrhage severity. RESULTS Severe postpartum hemorrhage occurred in 952 women (20.9%). In women with postpartum hemorrhage, factors independently associated with severity were: primiparity; previous postpartum hemorrhage; previous cesarean delivery; cervical ripening; prolonged labor; and episiotomy; and delay in initial care for postpartum hemorrhage. Also associated with severity was 1) administration of oxytocin more than 10 minutes after postpartum hemorrhage diagnosis: 10-20 minutes after, proportion with severe postpartum hemorrhage 24.6% compared with 20.5%, adjusted OR 1.38, 95% CI 1.03-1.85; more than 20 minutes after, 31.8% compared with 20.5%, adjusted OR 1.86, CI 1.45-2.38; 2) manual examination of the uterine cavity more than 20 minutes after (proportion with severe postpartum hemorrhage 28.2% versus 20.7%, adjusted OR 1.83, 95% CI 1.42-2.35); 3) call for additional assistance more than 10 minutes after (proportion with severe postpartum hemorrhage 29.8% versus 24.8%, adjusted OR 1.61, 95% CI 1.23-2.12 for an obstetrician, and 35.1% compared with 29.9%, adjusted OR 1.51, 95% CI 1.14-2.00 for an anesthesiologist); 4) and delivery in a public non-university hospital. Epidural analgesia was found to be a protective factor against severe blood loss in women with postpartum hemorrhage. CONCLUSION Aspects of labor, delivery, and their management; delay in initial care; and place of delivery are independent risk factors for severe blood loss in women with postpartum hemorrhage caused by atony. LEVEL OF EVIDENCE II.