Date Published: September 24, 2019
Publisher: Public Library of Science
Author(s): Kathryn E. Fitzpatrick, Jennifer J. Kurinczuk, Sohinee Bhattacharya, Maria A. Quigley, Gordon C. Smith
Abstract: 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 < 0.001), a blood transfusion (1.14%, n = 324 versus 0.50%, n = 226, aOR 2.3, 95% CI 1.9–2.8, p < 0.001), puerperal sepsis (0.27%, 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 < 0.001) and experience adverse perinatal outcomes including perinatal death, admission to a neonatal unit, resuscitation requiring drugs and/or intubation, and an Apgar score < 7 at 5 minutes (7.99%, n = 2,049 versus 6.37%, n = 2,570, aOR 1.6, 95% CI 1.5–1.7, p < 0.001). However, women who had a planned VBAC were more likely than those delivering by ERCS to breastfeed at birth or hospital discharge (63.6%, n = 14,906 versus 54.5%, n = 21,403, adjusted risk ratio [aRR] 1.2, 95% CI 1.1–1.2, p < 0.001) and were more likely to breastfeed at 6–8 weeks postpartum (43.6%, n = 10,496 versus 34.5%, n = 13,556, aRR 1.2, 95% CI 1.2–1.3, p < 0.001). The effect of planned mode of delivery on the mother’s risk of having a postnatal stay greater than 5 days, an overnight readmission to hospital within 42 days of birth, and other puerperal infection varied according to whether she had any prior vaginal deliveries and, in the case of length of postnatal stay, also varied according to the number of prior cesarean sections. The study is mainly limited by the potential for residual confounding and misclassification bias.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.
Partial Text: Cesarean section is now one of the most common surgical procedures performed, with many parts of the world having seen a sharp rise in their cesarean section rates in recent years [1–4]. In the United Kingdom, nearly 30% of all births are now delivered by cesarean section [5–7]. The rise in cesarean section rates has led to an increasing proportion of women embarking on a subsequent pregnancy with a history of previous cesarean section. Broad policy consensus in high-income countries supports offering pregnant women who have had previous cesarean section a choice between planning to have another cesarean, known as an elective repeat cesarean section (ERCS), or attempting a vaginal birth, known as a planned vaginal birth after previous cesarean (VBAC), also known as a trial of labor after previous cesarean (TOLAC). This is provided that they do not have contraindications to planned VBAC such as placenta previa or transverse lie.
In total, 74,043 singleton term births to women with one or more previous cesarean sections were identified as meeting the study eligibility criteria (Fig 1). Of these, 28,464 (38.4%) were to women classified as having a planned VBAC, and 45,579 (61.6%) were to women classified as having an ERCS. The ERCS rate among this group of women increased each year during the study period, from 50.5% in 2002 to 72.4% in 2015. Table 1 shows the characteristics of the study population by planned mode of delivery. Women who had a planned VBAC were more likely than those who had an ERCS to be younger, born outside the UK, be sole registered mothers (no partner or husband registered on the birth certificate), and have a lower socioeconomic status. They were also more likely to have just one prior cesarean section, have had one or more prior vaginal deliveries, have a shorter interpregnancy interval, be smokers at booking for pregnancy care, have a hypertensive disorder, have prelabor rupture of membranes, have delivered at late term (39–41 weeks gestation), and have delivered an infant less than the 10th centile for birth weight. They were less likely than women who had an ERCS to be overweight or obese, to have diabetes, and to have delivered an infant more than the 90th centile for birth weight.