Undergoing a Caesarean section is unlikely to cause problems with future fertility, according to researchers.
A study of more than one million low-risk first-time mothers in English NHS hospitals has shown the medical and social circumstances behind a decision to operate may be associated with apparent falls in fertility rather than the procedure itself.
The research was carried out by the Royal College of Obstetricians and Gynaecologists and the London School of Hygiene and Tropical Medicine. It was published in the journal Human Reproduction and examined births between April 2000 and March 2012.
Among low-risk first-time mothers, 224,024, or 21.4%, were delivered by Caesarean section, with fewer than 4% having an elective Caesarean section, or one planned in advance.
“We have found having a Caesarean section as a first-time mother leads to only a very small effect on subsequent fertility”
All types of Caesarean section were associated with a reduced subsequent birth rate, compared with those who had vaginal deliveries, but the size of the reduction varied among different groups of women.
The smallest reduction was for an elective Caesarean section for a breech baby − one in feet-first position − where a woman had no other complications during pregnancy.
The largest was for women having an elective Caesarean section for medical reasons.
Previous studies have reported that delivery by Caesarean is associated with fewer subsequent pregnancies and babies, as well as longer intervals between pregnancies.
A 2004 study by researchers from the University of Dundee found that women who had their first child by Caesarean were more likely to report having problems conceiving again, compared to women who had a vaginal delivery using instruments such as forceps.
Dr Tahir Mahmood, from the office for research and clinical audit at the RCOG and a co-author of the new paper, said: “The possible effect of Caesarean section on subsequent fertility is important as the age of first-time mothers continue to rise, along with the rates of Caesarean section.
“This is the largest cohort study to date looking at the association between mode of delivery and fertility, and to minimize the risk of bias we focused on low-risk pregnancies.
“By carefully distinguishing between different complications of pregnancy, we have found that having a Caesarean section as a first-time mother leads to only a very small effect on subsequent fertility.
“The circumstances behind the procedure may have a bigger impact and may explain the reduction in fertility apparent in previous studies.”
“This [study] does not negate the other negative effects of Caesarean sections”
Louise Silverton, director for midwifery at the Royal College of Midwives, said: “The fact that the effects on fertility may be minimal should go some way to reassure those women for whom a Caesarean is needed and who may want another child in the future.
“However, even though there is less effect on fertility than was assumed, this does not negate the other negative effects of Caesarean sections,” she said.
“We should continue to try to reduce the number of Caesarean sections amongst first-time mothers. We should also continue to encourage women who can, to consider a vaginal birth for the next and subsequent pregnancies,” she added.
“One of the ways this can be done is by promoting and providing more midwife-led care where woman are less likely to have a Caesarean section and other interventions.”