Placental abruption: assessing trends in risk factors over time

Abstract Purpose To evaluate changes in the independent contribution of different risk factors for placental abruption over time. Methods In this retrospective nested case control study, trends of change in ORs for known risk factors for placental abruption occurring in three consecutive eight-year intervals were compared. A univariate assessment of factors associated with placental abruption and two multivariable logistic regression models were constructed in order to identify independent risk factors for placental abruption. Trends of change in the incidence and specific contribution of various risk factors were compared along the study time period. Results During the study period 295,946 pregnancies met the inclusion criteria, of these, 2170 (0.73%) were complicated with placental abruption. Using logistic regression models, previous cesarean delivery, in vitro fertilization (IVF) pregnancy, hypertensive disorders, polyhydramnios and inadequate prenatal care were recognized as independent risk factors for placental abruption. While the relative contribution of IVF pregnancy and polyhydramnios to the overall risk for abruption decreased over the course of the study, previous cesarean delivery became a stronger contributor for placental abruption. Conclusion In our study, a change over time in the specific contribution of different risk factors for placental abruption has been demonstrated.