Prepregnancy risk factors for placental abruption.

<bold>Background: </bold>To define the prepregnancy risk factors for placental abruption.<bold>Methods: </bold>One hundred and ninety-eight women with placental abruption and 396 control women without placental abruption were retrospectively identified among 46,742 women who delivered at a tertiary referral university hospital between 1997 and 2001. Relevant historical and clinical variables were compared between the groups. Multivariate logistic regression analysis was applied to identify independent risk factors.<bold>Results: </bold>The overall incidence of placental abruption was 0.42%. Placental abruption recurred in 8.8% of the cases. The independent risk factors were smoking (OR 1.7; 95% CI 1.1, 2.7), uterine malformation (OR 8.1; 1.7, 40), previous cesarean section (OR 1.7; 1.1, 2.8), and history of placental abruption (OR 4.5; 1.1, 18).<bold>Conclusions: </bold>Although univariate analysis identified many risk factors, only smoking, uterine malformation, previous cesarean section, and history of placental abruption remained significant after multivariate analysis, increasing the risk of placental abruption in subsequent pregnancy. It may be possible to approximate the risk for placental abruption based on these simple prepregnancy risk factors. [ABSTRACT FROM AUTHOR]