Aberdeen University, Aberdeen Maternity Hospital, Foresterhill, Aberdeen, Scotland, UK 1 To whom correspondence should be addressed. e-mail: m.a.porter{at}abdn.ac.uk
Dear Sir,
We read with interest the paper by Murphy et al. reporting an association between Caesarean Section (CS) and subfertility (Murphy et al., 2002). That there is a link between CS and subsequent infertility, has been known for a while (Hemminki, 1996
), as has the existence of a relationship between subfertility and subsequent CS (Pandian et al., 2001
). Despite rising CS rates, this topic has not been widely studied and Murphy and colleagues contribution is most welcome. The prospective nature of their study allows them confidently to suggest that the relationship in the former case is a causal one, with CS contributing in some unknown way to a physiological inability to conceive.
Certain aspects of their paper merit further comment. Firstly, in response to the authors claim that the negative association between CS and future fertility is a new finding, we would like to point out that this was reported more than a decade ago (Hall et al., 1989). Secondly, as the authors acknowledge in their introduction, time to conception may not reflect the true fertility status of a population as it fails to account for couples who do not conceive at all. Thirdly, there are other data that have not been presented in this paper; these include numbers of couples who sought help in order to become pregnant. There is also no information about the type (emergency/elective) or the circumstances of the previous CS. Finally, despite the large overall sample size of 14 541 pregnancies, the total number of women with previous CS numbered only 422. This made it difficult to make comparisons between CS and non-CS groups among those taking >3 years to conceive.
We feel that the relationship between CS and subsequent sub-fertility is more complex than this paper suggests. What is needed is a more detailed approach using a blend of quantitative and qualitative methods to address womens views of their experiences. Many women and their partners find CS sufficiently traumatic to discourage them from having another baby for some time (Still et al., 1993; Jolly et al., 1999
). A difficult delivery may also cause problems within a couples relationship. Those who do plan another child may have a more ambivalent attitude to trying or the non-use of contraception than those who have had a straightforward vaginal delivery. Murphy et al. rightly call for more research to confirm their findings including an examination of additional reproductive outcomes such as miscarriage and ectopic pregnancy. We are currently using patient questionnaires and face-to-face interviews to collect such data from 1661 women with subfertility following CS in the Grampian region. We hope that our results will provide further insight into the nature of the association between CS and subsequent subfertility and show whether this phenomenon is voluntary or involuntary. At the same time, we are aware of the limitations of all observational studies. The media interest generated by this study and the potential obstetric implications of the results highlight the need for a responsible attitude towards reporting findings of this kind.
References
Hall, M.H., Campbell, D.M., Fraser, C. and Lemon, J. (1989) Mode of delivery and future fertility. Br. J. Obstet. Gynecol., 96, 12971303.[ISI][Medline]
Hemminki, E. (1996) Impact of caesarean section on future pregnancya review of cohort studies. [Review]. Paediat. Perinat. Epidemiol., 10, 366379.[ISI][Medline]
Jolly, J., Walker, J. and Bhabra, K. (1999) Subsequent obstetric performance related to primary mode of delivery. Br. J. Obstet. Gynecol., 106, 227232.[ISI][Medline]
Murphy, D.J., Stirrat, G.M., Heron, J. and the ALSPAC Study Team (2002) The relationship between caesarean section and subfertility in a population-based sample of 14 541 pregnancies. Hum. Reprod., 17, 19141917.
Pandian, S., Bhattacharya, S., and Templeton, A. (2001) A Review of unexplained infertility and obstetric outcome: a 10 year review. Hum. Reprod., 16, 25932597.
Still, L., Campbell, D., Hall, M. and Kenyon, N. (1993) Relative infertility after caesarean section: voluntary or involuntary. Br. J. Obstet. Gynecol., 100, 293294.