A new study conducted by the Office for Research and Clinical Audit (ORCA) at the Royal College of Obstetricians and Gynaecologists and the London School of Hygiene & Tropical Medicine has shown that almost two thirds of women who attempt a natural delivery after having a caesarean section for the birth of their first baby are successful.
Leading UK Obstetrician Mr Ashok Kumar says, “The results of this new study show that the majority of women who had a caesarean section for the delivery of their first baby but who attempt a natural delivery for their second baby are successful. This will be extremely helpful information for pregnant women when they are making decisions about their preferred method of giving birth.”
The researchers aimed to investigate the factors that determine the uptake and success rate of vaginal birth after a previous caesarean section. The data from 143,970 women, who had their first baby by caesarean section between 2004 and 2011, found that just over half (52%) attempted a subsequent vaginal birth for their second baby. It was found that younger women, aged 24 or less, were more likely to attempt a subsequent natural delivery than women aged over 34. Black women (62%) and Asian women (64%) were also found to have higher attempt rates for their second delivery when compared to white women (49%). Of the women who attempted a natural delivery after having a previous caesarean section almost two-thirds (63%) were successful, though researchers found that black women had a particularly low success rate when compared to white women, 50% versus 66% respectively. The study also showed that women aged over 34 had a lower success rate than women aged 24 or younger, 59% versus 69% respectively.
The reason for the first caesarean section was also found to strongly determine the likelihood of successful natural delivery in the second pregnancy. Furthermore, women with a history of failed induction of labour were almost twice as likely to fail when a subsequent natural delivery is attempted.
The researchers also found significant variation in the rate of attempted and successful natural delivery after caesarean section between NHS trusts, with almost a threefold variation in attempted natural delivery, ranging from 33% to 94%, and almost a twofold variation in successful vaginal delivery for the second baby, between 48% and 84%.
Hannah Knight, Office for Research and Clinical Audit, Royal College of Obstetricians and Gynaecologists, and lead researcher of the paper, said:
"The majority of women with an uncomplicated first caesarean section are candidates for attempting a vaginal birth after caesarean section, but our data found that only half of those women chose this option.” She added, "Interestingly, we also found an unexplained variation in the rate of attempted and successful vaginal birth after caesarean section between hospitals, which was independent of maternal demographic and clinical risk factors.”
The study was published in BJOG: An International Journal of Obstetrics and Gynaecology.
