The length of the second stage of labor in nulliparous, multiparous, grand-multiparous, and grand-grand multiparous women in a large modern cohort

Objective: The objectives of this study were to characterize the length of the second stage of labor in a large contemporary cohort of women with varying obstetrical histories and to investigate the factors associated with the length of the second stage. Study Design: This was a retrospective cohort study conducted at a tertiary medical center. Women with singleton spontaneous vaginal deliveries between the years 2005–2017 were included. The length of the second stage was compared between groups based on obstetrical history and maternal and obstetrical characteristics were evaluated to identify factors associated with the length of the second stage. Results: There were 100,759 deliveries included in the study. The second stage of labor was longest in nulliparous women with an epidural (median 96 min, interquartile range 53−142 min), which was 57 min longer than in nulliparous women without an epidural. In parous, grand-multiparous, grand-grand multiparous, and women with a prior cesarean delivery, all without an epidural, there was no clinically significant difference in the length of the second stage (median 6−7 min). The length of the second stage was significantly shorter in women delivering preterm compared to women delivering at term. Birthweight, previous cesarean delivery, gestational age, use of epidural analgesia, and induction of labor were all independently positively associated with the length of the second stage, while parity was negatively associated with the length of the second stage. Conclusion: The median length of the second stage of labor was considerably longer than historically described in nulliparous women and relatively shorter in parous women.