Cesarean delivery due to nonreassuring fetal heart rate: the effect of phase of labor on subsequent vaginal delivery success.

Introduction: To assess trial of labor and vaginal delivery rates in pregnancies following cesarean delivery (CD) due to nonreassuring fetal heart rate (NRFHR) according to phase of labor at cesarean.Materials and methods: This was a retrospective cohort of deliveries at a university hospital between 2009 and 2016. We compared primary CDs performed due to NRFHR during nonactive labor (cervical dilatation < 5 cm) and active labor (cervical dilatation ≥ 5 cm). Subsequent deliveries were reviewed for trial of labor and vaginal delivery rates, and maternal and obstetric outcomes compared.Results: Two hundred thirty-six patients underwent a CD during the nonactive phase of labor (nonactive phase group) and 126 patients during the active phase of labor (active phase group). Patients with a past active phase CD were more likely to attempt a trial of labor but equally likely to achieve a vaginal delivery. There was a trend for more CDs due to nonprogressive labor in this group. After adjustment, only past vaginal delivery was independently associated with a successful vaginal delivery, but not the phase of labor during which the past CD was performed.Conclusion: Our study points to a similar prognosis for patients with a past CD due to NRFHR, regardless of previous labor course.