The Prognosis of Unchanged Cervical Dilation in Active Labor during Labor Induction

The most common indication for cesarean delivery (CD) in the United States is failure to progress, with a large portion of these cases occurring in the setting of active labor dystocia. There is a current lack of data to guide counseling on the likelihood of requiring CD and associated maternal outcomes in the setting of unchanged cervical dilation in the active phase.

This is a retrospective cohort study of nulliparous patients with term singleton pregnancies who underwent induction of labor and progressed to active labor at a single institution between January 1, 2019 and December 31, 2019. Outcomes were compared among: (1) all who reached active labor, (2) active labor dystocia ≥2 hours, and (3) active labor dystocia ≥4 hours. The primary outcome was CD for any indication, with secondary outcomes of composite maternal morbidity and neonatal morbidity.

Among 1,309 eligible inductions, 1,095 (83.7%) reached active labor and were included. Those with dystocia ≥2 hours and dystocia ≥4 hours had significantly higher risk of requiring a CD (52.6 and 82.0%, respectively) when compared to those who reached active labor but did not experience dystocia (CD rate: 15.4%, p < 0.001). Composite maternal morbidity also increased by increasing length of labor dystocia. There were no significant findings pertaining to neonatal morbidity.

CD and maternal morbidity rates are significantly higher in nulliparous patients experiencing active labor dystocia, even at the 2-hour mark. These findings should inform counseling around CD risk as labor progresses.

· Even after 2 hours of active labor dystocia, maternal morbidity and cesarean risk increase.. · Neonatal morbidity was not affected by active labor dystocia.. · These findings can inform counseling in patients with active labor dystocia..