Short and longer-term outcomes for women and their children according to planned mode of birth after previous caesarean section

Background: Policy supports offering pregnant women with previous caesarean section a choice between elective repeat caesarean section (ERCS) or planning a vaginal birth after previous caesarean (VBAC), provided they have no contraindications to VBAC. However, robust comprehensive information on the associated outcomes to counsel women is lacking. This thesis investigated short and longer-term outcomes for women and their children according to planned mode of birth after previous caesarean section (CS).
Methods: A structured literature review and three population-based cohort studies of term singleton births in Scotland to women with ≥1 previous CSs were conducted. Logistic, modified Poisson or Cox regression were used to investigate the association between planned mode of birth after previous CS and 1) short-term maternal and perinatal outcomes; 2) women’s use of psychotropic medication in the first year postpartum; and 3) the child’s risk of having a record of special educational needs (SENs).
Findings: Planned VBAC compared to ERCS was associated with an increased risk of the mother having uterine rupture (0.24% vs. 0.04%, adjusted odds ratio[aOR] 7.3, 95%CI 3.9-13.9), a blood transfusion (1.14% vs. 0.50%, aOR 2.3, 95%CI 1.9-2.8), puerperal sepsis (0.27% vs. 0.17%, aOR 1.8, 95%CI 1.3-2.7), and surgical injury (0.17% vs. 0.09%, aOR 3.0, 95%CI 1.8-4.8) as well as an increased risk of 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% vs. 6.37%, aOR 1.6, 95%CI 1.5-1.7). However, women who had a planned VBAC were more likely than those giving birth by ERCS to breastfeed at birth or hospital discharge (63.6% vs. 54.5%, adjusted risk ratio[aRR] 1.2, 95%CI 1.1–1.2), and at 6–8 weeks postpartum (43.6% vs. 34.5%, aRR 1.2, 95%CI 1.2–1.3). Planned VBAC compared to ERCS was also associated with a reduced risk of the mother being dispensed any psychotropic medication (adjusted hazard ratio[aHR] 0.85, 95%CI 0.78–0.92), an antidepressant (aHR 0.83, 95%CI 0.76–0.90), and at least two consecutive antidepressants (aHR 0.83, 95%CI 0.75–0.91) in the first year postpartum, but was associated with a similar risk of the child having a record of any SENs (19.24% vs. 17.63%, aRR 1.04, 95%CI 0.99-1.09) or specific types of SEN.
Conclusions: While planned VBAC compared to ERCS was associated with an increased risk of serious birth-related maternal and perinatal complications, the absolute risk of birth-related complications was small for either birth approach. Furthermore, little evidence was found to support an association between planned mode of birth after previous CS and SENs in childhood. However, further studies examining the longer-term effects are needed, including to establish the relationship with women’s subsequent mental health. Overall, this thesis provides valuable information to help manage and counsel the increasing number of women with previous CS.

Keywords: Mode of birth
Perinatal mortality
Perinatal morbidity
Perinatal outcomes
Elective repeat caesarean section (ERCS)
Caesarean section
Maternal morbidity
Child outcomes
Vaginal birth after previous caesarean section (VBAC)
Maternal outcomes
Trial of labour after previous caesarean section (TOLAC)
Advisor: Kurinczuk, J