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

OBJECTIVE: To determine risk factors for a prolonged second stage of labor and evaluate the maternal and neonatal outcomes of such pregnancies.
METHODS: 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).
RESULTS: 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).
CONCLUSION: 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.