Caesarians and fertility: the truth behind the headlines

Rising rates of caesarean section (CS) during the last 20 years, combined with celebrities choosing to give birth this way, have resulted in considerable media activity whenever academic studies report any findings relating to CS. The press never fails to mention Victoria Beckham, Zoe Ball or Liz Hurley, among others, all deemed 'too posh to push', apparently demanding CS in order to control the timing of the delivery and to avoid damaging the birth canal. High profile women such as these are thought to have started a trend in women demanding CS without medical indications. The evidence suggests that there is no truth in this; ordinary women who request a CS have usually had CS before and are concerned about the risks of uterine rupture or have other good reasons for requesting operative delivery. Non-celebrities are perhaps more aware of the difficulties of looking after a small baby unaided, soon after what amounts to major abdominal surgery.

Our study linking primary mode of delivery and future fertility, published in the British Journal of Obstetrics & Gynaecology and mentioned in last week's BioNews, resulted in extensive media coverage and a spurious mention of those deemed 'too posh to push'. On the whole, we felt that most of the coverage was factual, accurate and balanced. Our study found that after adjusting for the effects of maternal age, social class and gestation at delivery, those who delivered by CS - whether emergency or elective - were less likely to have another baby than those who delivered vaginally and more likely to experience ectopic pregnancy. At 36.3 months, the average time to the next pregnancy following CS was six months longer than that following a vaginal delivery. We concluded that the mode of delivery had played a role in this reduced fertility but stressed the need for further studies to establish causality.

We are concerned, however, that some of the media coverage - particularly tabloid headlines such as 'Caesareans may harm fertility' and 'Caesareans hit hopes of having more babies' - may have conveyed the impression that CS has a deleterious effect on women's ability to become pregnant. The Daily Mail, for example, reported that 'some [women] are so traumatised that they avoid a repeat of the experience. Others take at least six months longer to conceive. Doctors fear that Caesarean deliveries may harm fertility by disrupting the reproductive system'. This may well be true, but we do not know for certain, and cannot speculate on the basis of the present study whether CS causes problems in conceiving. Several studies have examined the physiological effects of CS on future fertility and suggested mechanisms of operation including pelvic adhesions, infection, placental bed disruption and tubal damage but none has proved a definitive link between CS and impaired fertility. On the other hand, studies have suggested that women experiencing traumatic births, particularly emergency CS, are less likely to have more children. The relationship is further complicated by evidence from one of our previous studies that shows that pre-existing infertility is more likely to result in a caesarean delivery.

In an effort to provide the definitive answer, we have conducted and are in the process of publishing further studies examining the extent to which the reduced fertility following CS is voluntary or involuntary. This second study combines a large-scale retrospective postal survey of women having first babies by various modes of delivery in Aberdeen between 1980 and 1995, with a smaller in-depth interview study of respondents. The aim of the survey was to establish the extent to which women deliberately prevented or delayed further conceptions by consistent use of effective birth control (voluntary infertility) and the extent to which they tried for further pregnancies without success (involuntary infertility). It ascertained the characteristics of such women and the type of birth they had experienced. The interview study examined women's choices in more detail, focusing upon the role of socio-demographic and lifestyle factors as well as the birth experience. The results of these studies should be available shortly and will add to the bigger picture.

Overall, however, we feel that the media fixation with the few who 'demand' CS without medical reasons has distracted attention from the wider societal implications of a rising CS rate, falling birth rate and a rising incidence of women choosing to begin their families later in life.