Almost two-thirds of women who attempt a natural delivery after a previous Caesarean section are successful, while 37 per cent require an emergency Caesarean, according to research.
One of the biggest studies to examine natural delivery among women who had their first baby by Caesarean section found 63 per cent managed a vaginal delivery with their second baby, while the remainder needed an emergency operation to deliver their child.
Across the UK, 20 per cent to 25 per cent of all births are by C-section. In the study, which excluded women with known medical complications such as diabetes, just over half (52 per cent) of 143,970 women attempted a vaginal birth after a C-section (Vbac).
All the women had their first baby by C-section between 2004 and 2011.
Younger women aged 24 or under were more likely to attempt Vbac
Researchers found that younger women aged 24 or under were more likely to attempt Vbac than women aged over 34.
Black and Asian women were also found to have higher Vbac attempt rates for their second delivery compared to white women.
The reason for the first C-section was found to strongly determine the likelihood of successful natural delivery in the second pregnancy.
Furthermore, women whose first labour required an induction which then failed were almost twice as likely to have a failed Vbac.
The researchers also found variation in the rate of attempted and successful Vbac between NHS trusts.
There was almost a threefold variation in attempted Vbac, ranging from 33 per cent to 94 per cent, and almost a twofold variation in successful vaginal delivery for the second baby, between 48 per cent and 84 per cent.
Consultant obstetrician Tahir Mahmood said the study showed the majority of women were successful but risks were higher among women who had a previous C-section.
He said one in 200 women would experience a rupture of their scar while other risks included the tendency for the baby to experience more foetal distress.
The new data was published in BJOG: An International Journal of Obstetrics and Gynaecology.
Hannah Knight, from the Royal College of Obstetricians and Gynaecologists (RCOG), and lead researcher of the paper, said: “The majority of women with an uncomplicated first C-section are candidates for attempting Vbac, but our data found that only half of those women chose this option.
“Women from a non-white ethnic background were more likely than white women to attempt a Vbac, but the success rate in non-white women was lower. This could point to different patient preferences or a lack of access to elective repeat C-section for non-white women. Interestingly, we also found an unexplained variation in the rate of attempted and successful Vbac between hospitals, which was independent of maternal demographic and clinical risk factors.
“An informed discussion about whether or not to attempt a vaginal delivery after a C-section requires an assessment of the risk of emergency Caesarean, and this paper provides valuable information both for women and the obstetricians and midwives caring for them.”