Becker DA, et al. - The labor curves of nulliparous and multiparous women between 23.0 and 34.0 weeks of gestation who underwent induction of labor and achieved vaginal delivery were analyzed. Performing a retrospective cohort study of all live singletons delivered vaginally after medically indicated induction of labor between 23.0 and 34.0 weeks of gestation from 2011 through 2014 at their institution, researchers included 67 nulliparous and 69 multiparous women. Similar rates of change from 1 to 3 cm of dilation were observed in the two groups (median 3.6 hours nulliparous and 3.4 hours multiparous). Progression from 3 to 6 cm underwent more slowly in nulliparous women than multiparous women (median 10 hours vs 4.4 hours). After 6 cm, both groups rapidly progressed to 10 cm (median 0.3 hours vs 0.3 hours). This indicates that multiparous women take less time for early preterm labor induction owing to more rapid progression from 3 to 6 cm. At the 95th percentile, vaginal delivery was observed in both nulliparous and multiparous women, even with latent labor lasting well longer than 24 hours.