Is It Safe to Have a Vaginal Birth after Cesarean Section? Interview with:
“Childbirth” by DAVID Swift is licensed under CC BY 2.0
Dr. Carmen Young
Department of Obstetrics and Gynecology
University of Alberta What is the background for this study?

Response: For women who have had a single previous cesarean section, the optimal mode of delivery in a subsequent pregnancy is controversial. This is because there are risks and benefits to attempting a vaginal birth after cesarean section (VBAC) or having an elective repeat cesarean section. Attempted VBAC is associated with a higher risk of uterine rupture and other maternal and infant complications. Repeat cesarean sections are associated with an increased risk of surgical complications and placental complications in subsequent pregnancies. Furthermore, it is difficult to predict which patients will have a successful VBAC.

This study is unique in that it uses recent Canadian data, allowing assessment of the impact of contemporary obstetrical care on maternal and neonatal outcomes in Canada. What are the main findings?

Response: We conducted a study using information on all women in Canada (excluding Quebec) who had a previous caesarean delivery and subsequently delivered between 2003 and 2015.

Our study found that although the number of women with a previous cesarean delivery increased from 2003 to 2014, rates of attempted . vaginal birth after cesarean section and rates of success after a trial of labour were essentially unchanged.

The absolute rates of adverse maternal and neonatal outcomes are low with both attempted VBAC and elective repeat cesarean delivery. For example, the risks of uterine rupture and infant death were well less than one percent. Therefore, both are reasonable options for women in general.

However, attempted vaginal birth after cesarean section continues to be associated with higher relative rates of severe adverse maternal and neonatal outcomes compared with an elective repeat cesarean delivery. Uterine rupture was over six times more likely, serious maternal morbidity and mortality was almost two times more likely and serious infant morbidity and mortality was nearly one and a half times more likely for those attempting VBAC compared to those with an elective repeat cesarean section.

Women and infants with a successful  vaginal birth after cesarean section have lower rates of adverse outcomes compared with women having an elective repeat cesarean. Serious maternal morbidity and mortality and neonatal respiratory distress syndrome were about half the risk compared with an elective repeat cesarean. However, those with a failed VBAC had substantially higher rates of adverse outcomes. Serious maternal morbidity and mortality was over two and half times as likely and neonatal death three times as likely with a failed VBAC compared with an elective repeat cesarean. This highlights the importance of patient selection for attempting VBAC.

Our study also found that there has been a temporal worsening of infant, but not maternal, outcomes after attempted VBAC between 2003 and 2015. What should readers take away from your report?

Response: The study highlights the importance of appropriate patient selection for attemptin gvaginal birth after cesarean section and careful monitoring of their labour and delivery to optimize safety for these women and their infants. If patients are properly selected and managed, both options for delivery are reasonable and of low risk

For women who are considered candidates for an attempted VBAC, the choice between an elective repeat cesarean delivery and an attempted vaginal birth after cesarean section depends on a woman’s evaluation and interpretation of risks, as this is very personal. Although the chance of severe maternal or infant complications is overall small (absolute risks), the risks are substantially higher for women attempting VBAC compared with an elective repeat cesarean (relative risks). The choice is also impacted by a woman’s desire for a vaginal delivery and whether she is planning a small or large family as repeated caesareans are associated with increasing maternal and infant risks, including placental complications in future pregnancies. What recommendations do you have for future research as a result of this work?

Response: Future study could focus on the cause for the temporal worsening of neonatal outcomes. It will be important to examine patient characteristics and obstetrical practices to determine what underlines the increase in adverse neonatal outcomes associated with attempted VBAC in recent years. Such analyses will provide clues as to whether it is problematic patient section or management that is it the issue. 

Dr. Carmen Young does not have any disclosures.


Mode of delivery after a previous cesarean birth, and associated maternal and neonatal morbidity

Carmen B. Young, Shiliang Liu, Giulia M. Muraca, Yasser Sabr, Tracy Pressey, Robert M. Liston and K.S. Joseph; for the Canadian Perinatal Surveillance System

CMAJ May 07, 2018 190 (18) E556-E564; DOI:

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Last Updated on May 7, 2018 by Marie Benz MD FAAD