THE NUMBER OF women who attempt vaginal birth (known as VBAC in maternal medicine) after a previous Caesarean operation remains low – and the risk to them and their infants remains higher when compared to having another C-section, the Canadian Medical Association has found.

Researchers 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.

It found that the number of adverse outcomes – to either baby or mother are low.

“Both are reasonable options for women in general,” says Dr. Carmen Young, University of Alberta.

“However, attempted VBAC continues to be associated with higher relative rates of severe adverse maternal and neonatal outcomes compared with an elective repeat Caesarean delivery.”

It is a common perception that once a woman has had a C-section, she should not subsequently attempt vaginal birth and the authors of this research say planning the mode of delivery for such women is challenging for both the patient and her care provider.

They found that, although the number of women with a previous cesarean delivery increased from 2003 to 2014, the amount of attempted VBAC and their success rates were essentially unchanged.

Though the rates of adverse effects (including death of mothers and infants) were low in both attempted VBAC and a repeat cesarean delivery, Dr Young advises caution.

With VBAC, there is a higher risk of uterine rupture, hemorrhage and other maternal and infant complications. Repeat Caesarean sections also come with their own share of risks due to surgical and placental complications in subsequent pregnancies.

Risks include uterine rupture and hemorrhages. Shutterstock / Africa Studio Shutterstock / Africa Studio / Africa Studio

“This topic is an important issue because rates of Caesarean section continue to rise and the most common single indication for a Caesarean delivery is a prior Caesarean delivery,” says Dr Young.

Once a woman has had two cesarean deliveries, she is very unlikely to have a subsequent vaginal delivery due to high maternal and neonatal risks associated with labour.

The study also found that infant, but not maternal, outcomes have worsened between 2003 and 2015 after attempted VBAC.

According to the organisation, the research highlights the importance of appropriate patient selection for attempting VBAC and careful monitoring of labour and delivery for the safety of both mothers and infants.

“For women who may be candidates for an attempted VBAC, the choice between an elective repeat cesarean delivery and an attempted VBAC depends on the woman’s desire for a vaginal delivery, her tolerance for risk and whether she is planning a small or large family,” says Dr Young.