Maternal and neonatal outcomes in patients with a prolonged second stage of labor

To determine risk factors for a prolonged second stage of labor and evaluate the maternal and neonatal outcomes of such pregnancies.

We reviewed all 7818 patients who delivered at the University of Illinois at Chicago from 1996 to 1999. Excluding nonvertex and multiple gestations, 6791 reached the second stage. Group 1 (n = 6259) consisted of patients with a second stage of 120 minutes or less; group 2, greater than 120 minutes (n = 532 [7.8%]); group 2A, 121-240 minutes (n = 384 [5.7%]); and group 2B, greater than 240 minutes (n = 148 [2.2%]). We compared pregnancy outcomes for these groups with respect to maternal and neonatal morbidity factors using chi(2), Student t, and Wilcoxon rank-sum tests (significance, P <.05).

Vaginal delivery rates were 98.7% (group 1), 84.0% (group 2), 90.2% (group 2A), and 65.5% (group 2B). Group 2 had higher rates of perineal trauma, episiotomy usage, chorioamnionitis, postpartum hemorrhage, and operative vaginal delivery than group 1 (P <.001, all comparisons). Group 2B had higher rates of episiotomy usage, operative vaginal deliveries, and perineal trauma than group 2A (P <.001, all comparisons). The neonatal morbidity rates were similar for the three groups. Diabetes, preeclampsia (P <.023), macrosomia, nulliparity, chorioamnionitis, oxytocin usage, and labor induction were each independently associated with an increased risk of a prolonged second stage (all but preeclampsia, P <.001).

A prolonged second stage is associated with a high rate of vaginal delivery, but a high rate of maternal, though not neonatal, morbidity was observed. Certain antenatal and intrapartum conditions are associated with a prolonged second stage of labor.