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.