METHODS: A population-based cohort study including 1,114,071 women with singleton pregnancies who gave birth in Sweden from January 1, 1997 through December31, 2008, who were divided into six body mass index (BMI) classes.
Obese women (class I–III) were comparedwith normal-weight women concerning the risk for postpartum hemorrhage after suitable adjustments.
The use of heparin-like drugs over the BMI strata was analyzed in a subgroup.