Vaginal birth after cesarean (VBAC): fear it or dare it? An evaluation of potential risk factors.

Objectives: The consultation of women aspiring a vaginal birth after caesarean may be improved by integrating the individual evaluation of factors that predict their chance of success. Retrospective analysis of correlating factors for all trials of labor after caesarean that were conducted at the Department of Obstetrics of Charité-Universitätsmedizin Berlin, Campus Virchow Clinic from 2014 to October 2017.

Methods: Of 2,151 pregnant women with previous caesarean, 408 (19%) attempted a vaginal birth after cesarean. A total of 348 women could be included in the evaluation of factors, 60 pregnant women were excluded because they had obstetric factors (for example preterm birth, intrauterine fetal death) that required a different management.

Results: Spontaneous delivery occurred in 180 (51.7%) women and 64 (18.4%) had a vacuum extraction. 104 (29.9%) of the women had a repeated caesarean delivery. The three groups showed significant differences in body mass index, the number of prior vaginal deliveries and the child's birth weight at cesarean section. The indication for the previous cesarean section also represents a significant influencing factor. Other factors such as maternal age, gestational age, sex, birth weight and the head circumference of the child at trial of labor after caesarean showed no significant influence.

Conclusions: The clear majority (70.1%) of trials of labor after caesarean resulted in vaginal delivery. High body mass index, no previous spontaneous delivery, and fetal distress as a cesarean indication correlated negatively with a successful vaginal birth after cesarean. These factors should be used for the consultation of pregnant women.