Active-phase labor arrest: oxytocin augmentation for at least 4 hours.

OBJECTIVE: To assess a labor-management protocol that mandated at least 4 hours of oxytocin augmentation before cesarean delivery for active-phase labor arrest.

METHODS: We prospectively evaluated term gravidas in spontaneous labor with active-phase labor arrest (cervix at least 4 cm dilated and 1 cm or less of cervical progress in 2 hours). Exclusion criteria included nonvertex presentation, previous cesarean, multiple gestation, and a nonreassuring fetal heart rate tracing or chorioamnionitis at the time of labor arrest. After the diagnosis of active-phase arrest, oxytocin was initiated with an intent to achieve a sustained uterine contraction pattern of greater than 200 Montevideo units. Cesarean delivery was not performed for labor arrest until at least 4 hours of a sustained uterine contraction pattern of greater than 200 Montevideo units, or a minimum of 6 hours of oxytocin augmentation if this contraction pattern could not be achieved.

RESULTS: Five hundred forty-two women were managed by the protocol, and 92% delivered vaginally. The subsequent vaginal delivery rate for parous women who had not progressed (1 cm of cervical dilation or less) despite 2 hours of oxytocin augmentation was 91%, and it was 74% for nulliparas. With no labor progress after 4 hours of oxytocin augmentation, the subsequent vaginal delivery rates were 88% for parous women and 56% for nulliparas. There were no severe maternal complications. One neonate had persistent fetal circulation and one had a positive blood culture, but both did well.

CONCLUSION: Extending the minimum period of oxytocin augmentation for active-phase labor arrest from 2 to at least 4 hours was effective and safe.