The investigators propose a parallel group randomized clinical trial of intrapartum nipple
stimulation versus exogenous oxytocin infusion for nulliparous women undergoing induction of
labor near term. The central hypothesis is that intrapartum nipple stimulation to induce
labor increases spontaneous vaginal delivery, improves patient-centered outcomes such as
childbirth satisfaction, labor agentry, and pain scores, and reduces adverse neonatal and
maternal outcomes in nulliparous women. The investigators will pursue the following specific
aims: 1) Assess the effectiveness of intrapartum nipple stimulation on the rate of
spontaneous vaginal delivery in nulliparous women (Primary Aim), 2) Determine the effect of
intrapartum nipple stimulation on the rate of adverse maternal and neonatal outcomes
(Secondary Aim #1), 3) Determine the impact of intrapartum nipple stimulation on
patient-centered outcomes (Secondary Aim #2) and 4) In a sub-cohort of women who are enrolled
in the trial, to measure the change in oxytocin concentration from baseline to time at which
patient achieves a regular contraction pattern, and to measure correlation between salivary
and serum oxytocin concentrations in patients undergoing induction of labor via intrapartum
nipple stimulation versus continuous exogenous oxytocin infusion. The investigators estimate
that randomizing a total of 562 women will provide adequate statistical power to detect
meaningful differences in the primary outcome.