Abstract
BACKGROUND: Term nulliparous women have the greatest variation across hospitals and providers in cesarean rates and therefore present an opportunity to improve quality through optimal care. We evaluated associations between provider type and mode of birth, including examination of intrapartum management in healthy, laboring nulliparous women. METHODS: Retrospective cohort study using prospectively collected perinatal data from a United States academic medical center (2005-2012). The sample included healthy nulliparous women with spontaneous labor onset and term, singleton, vertex fetus managed by either obstetricians or certified nurse-midwives. Univariate and multivariate logistic regression was used to compare labor interventions and mode of birth by provider type. RESULTS: A total of 1339 women received care by an obstetrician (n = 749) or nurse-midwife (n = 590). The cesarean rate was 13.4% (179/1339). Adjusting for maternal and pregnancy characteristics, care by obstetricians was associated with an increased risk of unplanned cesarean birth (adjusted odds ratio [aOR] 1.48 [95% confidence interval {CI} 1.04-2.12]) compared with care by midwives. Obstetricians more frequently used oxytocin augmentation (aOR 1.41 [95% CI 1.10-1.80]), neuraxial anesthesia (aOR 1.69 [95% CI 1.29-2.23]), and operative vaginal delivery with forceps or vacuum (aOR 2.79 [95% CI 1.75-4.44]). Adverse maternal or neonatal outcomes were not different by provider type across all modes of birth, but were more frequent in women with cesarean than vaginal births. DISCUSSION: In low-risk nulliparous laboring women, care by obstetricians compared with nurse-midwives was associated with increased risk of labor interventions and operative birth. Changes in labor management or increased use of nurse-midwives could decrease the rate of a first cesarean in low-risk laboring women.