Contemporary Labor Patterns and Maternal Age

OBJECTIVE:To evaluate labor progress and length according to maternal age. METHODS:Data were abstracted from the Consortium on Safe Labor, a multicenter retrospective study from 19 hospitals in the U.S. We studied 120,442 laboring gravid women with singleton, term, cephalic fetuses with normal outcomes and without a prior cesarean delivery from 2002 to 2008. Maternal age categories were younger than 20 years of age, 20–29 years of age, 30–39 years of age, and 40 years of age or older with the reference being younger than 20 years of age. Interval-censored regression analysis was used to determine median traverse times (progression centimeter by centimeter) with 95th percentiles adjusting for covariates (race, admission body mass index, diabetes, gestational age, induction, augmentation, epidural use, and birth weight). A repeated-measures analysis with an eighth-degree polynomial model was used to construct mean labor curves for each maternal age category stratified by parity. RESULTS:Traverse times for nulliparous women demonstrated the time to progress from 4 to 10 cm decreased as age increased up to age 40 years (median 8.5 hours compared with 7.8 hours in those 20–29 years of age group and 7.4 hours in the 30–39 years of age group, P