Planned mode of delivery after previous cesarean section and short-term maternal and perinatal outcomes: A population-based record linkage cohort study in Scotland

BackgroundPolicy consensus in high-income countries supports offering pregnant women with previous cesarean section a choice between planning an elective repeat cesarean section (ERCS) or attempting a vaginal birth, known as a planned vaginal birth after previous cesarean (VBAC), provided they do not have contraindications to planned VBAC. However, robust comprehensive information on the associated outcomes to counsel eligible women about this choice is lacking. This study investigated the short-term maternal and perinatal outcomes associated with planned mode of delivery after previous cesarean section among women delivering a term singleton and considered eligible to have a planned VBAC.Methods and findingsA population-based cohort of 74,043 term singleton births in Scotland between 2002 and 2015 to women with one or more previous cesarean sections was conducted using linked Scottish national datasets. Logistic or modified Poisson regression, as appropriate, was used to estimate the effect of planned mode of delivery on maternal and perinatal outcomes adjusted for sociodemographic, maternal medical, and obstetric-related characteristics. A total of 45,579 women gave birth by ERCS, and 28,464 had a planned VBAC, 28.4% of whom went on to have an in-labor nonelective repeat cesarean section. Compared to women delivering by ERCS, those who had a planned VBAC were significantly more likely to have uterine rupture (0.24%, n = 69 versus 0.04%, n = 17, adjusted odds ratio [aOR] 7.3, 95% confidence interval [CI] 3.9–13.9, p n = 324 versus 0.50%, n = 226, aOR 2.3, 95% CI 1.9–2.8, p n = 76 versus 0.17%, n = 78, aOR 1.8, 95% CI 1.3–2.7, p = 0.002), and surgical injury (0.17% versus 0.09%, n = 40, aOR 3.0, 95% CI 1.8–4.8, p n = 2,049 versus 6.37%, n = 2,570, aOR 1.6, 95% CI 1.5–1.7, p n = 14,906 versus 54.5%, n = 21,403, adjusted risk ratio [aRR] 1.2, 95% CI 1.1–1.2, p n = 10,496 versus 34.5%, n = 13,556, aRR 1.2, 95% CI 1.2–1.3, p ConclusionsAmong women considered eligible to have a planned VBAC, planned VBAC compared to ERCS is associated with an increased risk of the mother having serious birth-related maternal and perinatal complications. Conversely, planned VBAC is associated with an increased likelihood of breastfeeding, whereas the effect on other maternal outcomes differs according to whether a woman has any prior vaginal deliveries and the number of prior cesarean sections she has had. However, the absolute risk of adverse outcomes is small for either delivery approach. This information can be used to counsel and manage the increasing number of women with previous cesarean section, but more research is needed on longer-term outcomes.