Length of the Second Stage of Labor in Women Delivering Twins.

<bold>Objective: </bold>To evaluate the length of the second stage of labor in twin deliveries and to compare the length of the second stage in twin and singleton gestations.<bold>Methods: </bold>This is a retrospective cohort study from three large hospitals in Israel. Clinical data were collected from the electronic medical record. The primary outcome was the length of the second stage (the time from documented 10-cm dilation until spontaneous vaginal delivery of the first twin). Multivariable linear regression was used to examine the association of clinical factors with the length of the second stage. The length of the second stage in twin and singleton pregnancies was compared.<bold>Results: </bold>From 2011 to June, 2020, there were 2,009 twin deliveries and 135,217 singleton deliveries. Of the twin deliveries, 655 (32.6%) of the patients were nulliparous (95th percentile length of the second stage 3 hours and 51 minutes), 1,235 (61.5%) were parous (95th percentile 1 hour 56 minutes), and 119 (5.9%) were grand multiparous (five or more prior deliveries) (95th percentile 1 hour 24 minutes). In women delivering twins, epidural use was associated with a statistically significant increase in the length of the second stage of 40 minutes in nulliparous patients and 15 minutes in parous patients. In all groups, the length of the second stage was longer in patients delivering twins compared with singletons. Second-stage length longer than the 95th percentile in twins was associated with admission to the neonatal intensive care unit and need for phototherapy.<bold>Conclusion: </bold>Second-stage labor is longer in twins than singletons and is associated with obstetric history. Normal ranges for the second stage may be useful in guiding clinical practice. [ABSTRACT FROM AUTHOR]