Does length of labor vary by maternal age?

Abstract

The purpose of this study was to examine lengths of first and second stages of labor across maternal age groups to determine whether different norms should be established. We conducted a retrospective cohort study of all laboring, term, singleton, and cephalic deliveries at a single institution between 1980-2001. Median lengths of labor were compared among 6 maternal age groups. Statistical comparisons were made using Kruskal-Wallis and Wilcoxon rank sum tests. Multivariable linear and logistic regression models were performed. Among 31,976 births, length of labor differed significantly by maternal age for both nulliparous and multiparous women. Younger nulliparous women (age, <20 yrs) had a shorter median second stage by up to 97 minutes (P < .001) than older nulliparous women (age, >39 yrs). After we controlled for potential confounders, we found that older women had a persistently higher likelihood of experiencing longer labor and prolonged labor than younger women. Length of labor and prolonged labor increases with increasing maternal age.