Prolonged second stage of labor and risk of subsequent spontaneous preterm birth

A second stage of labor of ≥4 hours in the first pregnancy was not associated with an increased risk of subsequent spontaneous preterm birth and was associated with a high rate (>70%) of vaginal birth. A second stage of labor of ≥7 hours did not appear to be associated with an increased risk of preterm birth, when we adjusted for mode of first delivery. There was a nonsignificant increase in the risk of preterm birth in those who delivered via cesarean section after a second stage of labor of ≥7 hours.