Does length of labor vary by maternal age?

Objective: 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. Study Design: 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. Results: 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. Conclusion: Length of labor and prolonged labor increases with increasing maternal age.