Population-based risk for peripartum hysterectomy during low- and moderate-risk delivery hospitalizations

BACKGROUND: Postpartum hysterectomy is an obstetric procedure that carries significant maternal risk that is not well characterized by hospital volume. OBJECTIVE: The objective of this study was to determine risk for peripartum hysterectomy for women at low and moderate risk for the procedure. STUDY DESIGN: This population-based study used data from the Nationwide Inpatient Sample to characterize risk for peripartum hysterectomy. Women with a diagnosis of placenta accreta or prior cesarean and placenta previa were excluded. Obstetrical risk factors along with demographic and hospital factors were evaluated. Multivariable mixed-effects log-linear regression models were developed to determine adjusted risk. Based on these models receiver operating characteristic curves were plotted, and the area under the curve was determined to assess discrimination. RESULTS: Peripartum hysterectomy occurred in 1 in 1913 deliveries. Risk factors associated with significant risk for hysterectomy included mode of delivery, stillbirth, placental abruption, fibroids, and antepartum hemorrhage. These factors retained their significance in adjusted models: the risk ratio for stillbirth was 3.44 (95% confidence interval, 2.94-4.02), abruption 2.98 (95% confidence interval, 2.52-3.20), fibroids 3.63 (95% confidence interval, 3.22-4.08), and antepartum hemorrhage 7.15 (95% confidence interval, 6.16-8.32). The area under the curve for the model was 0.833. CONCLUSION: Peripartum hysterectomy is a relatively common event that hospitals providing routine obstetric care should be prepared to manage. That specific risk factors are highly associated with risk for hysterectomy supports routine use of hemorrhage risk-assessment tools. However, given that a significant proportion of hysterectomies will be unpredictable, the availability of rapid transfusion protocols may be necessary for hospitals to safely manage these cases.