Caesarean births 'reduce chance of conceiving again'

Women who give birth by Caesarean section take longer than other mothers to have more children, research shows. In a study of 14,541 women from the West Country, a Caesarean doubled the chance that conceiving a subsequent child would take more than a year.

Among women who had Caesareans and wanted another child, 12 per cent had to wait more than a year compared with 7 per cent among women who had natural births. The results, in the journal Human Reproduction, suggest Caesarean deliveries could damage fertility, although the reason is unclear.

Dr Deidre Murphy, of the obstetrics and gynaecology division at Bristol University, said the delay could be related to infection during the operation or disruption to the placenta, womb lining or fallopian tubes. "Further studies in other populations are needed to confirm our finding that Caesarean section may have a negative influence on future fertility," she said.

One in five women gives birth by Caesarean section. The rate of surgical deliveries has trebled in the past 25 years. The trend has been blamed on women demanding Caesareans because they are "too posh to push", a tendency to over-diagnose potential problems with unborn babies and a fear of litigation among obstetricians.

Women who have Caesareans are known to suffer more post-birth complications such as haemorrhaging, infection and uterine rupture than those who have vaginal births. But there has been little research on the effects of Caesareans on future fertility.

The study also looks at the ages of parents, drinking and smoking patterns, and history of using the contraceptive pill. It acknowledges that women with known fertility problems are more likely to be offered Caesarean births. But even after adjusting for these, the results show the surgery itself may cause secondary infertility in some women.

Dr Murphy, an obstetrician at St Michael's Hospital in Bristol, said: "The real worry is that more obstetricians are opting for Caesarean sections and more women are requesting them, but little attention has been paid to the potential consequences." Delays in conceiving could have a particular impact on the growing number of women who chose to delay childbirth until their 30s, she added.

The results show that women who have had two or more Caesareans are much more likely to experience subsequent delays in becoming pregnant, suggesting there is a cumulative effect on the risk of infertility. The study could also have failed to recognise the extent of the problem because it looked at women who succeeded in becoming pregnant. It did not take into account women who opted not to have another pregnancy after a Caesarean or those who failed to conceive.

Dr Murphy said: "This may be underestimating the true magnitude of the association. It is possible some women will choose not to have a further pregnancy because of the trauma of a section or will fail to achieve further pregnancy following Caesarean section."