Length of the second stage of labor among women achieving vaginal birth after cesarean.

Abstract

To characterize the length of the second stage of labor among women completing a first vaginal birth after a cesarean (VBAC), according to the stage of labor during primary cesarean delivery (CD). A retrospective cohort study of VBACs between 2011 and 2020. Study groups were divided as follows: CD not in labor, CD in the first stage of labor, and CD in the second stage of labor. The primary outcome was the length of the second stage. A total of 1310 VBACs were included. The timing of the primary CD was not associated with the duration of the second stage. The median second stage of duration of VBACs with previous first stage CD versus previous CD not in labor was 81 versus 106 min, respectively (P= 0.050). In multivariable linear regression, maternal age, birth weight, and epidural were independently associated with second-stage length. Maternal and neonatal outcomes did not differ between study groups and were not affected by the second-stage length. When stratified according to the labor stage of the primary CD, second-stage duration among women completing VBACs was not associated with labor stage at the primary CD. Extremes of the second-stage duration were not associated with increased morbidity.