Complications of term pregnancies beyond 37 weeks of gestation

OBJECTIVE: To estimate when rates of pregnancy complications increase beyond 37 weeks of gestation. METHODS: We designed a retrospective, cohort study of all women delivered beyond 37 weeks of gestational age from 1992 to 2002 at a single community hospital. Rates of perinatal complications by gestational age were analyzed with both bivariate and multivariable analyses. Statistical significance was designated by P < .05. RESULTS: Among the 45,673 women who delivered at 37 completed weeks and beyond, the rates of meconium and macrosomia increased beyond 38 weeks of gestation (P < .001), the rates of operative vaginal delivery, chorioamnionitis, and endomyometritis all increased beyond 40 weeks of gestation (P < .001), and rates of intrauterine fetal death and cesarean delivery increased beyond 41 weeks of gestation (P < .001). CONCLUSION: Risks to both mother and infant increase as pregnancy progresses beyond 40 weeks of gestation.