We were very pleased to hear that our article, ‘Multiple repeat caesarean section in the UK: incidence and consequences to mother and child. A national prospective cohort study’, was discussed by colleagues at East Surrey Hospital journal club, and we would like to thank them for their interest and comments.
The decision to examine outcomes in women undergoing their fifth or more caesarean section (CS) was a pragmatic one, which enabled us to utilise the UK Obstetric Surveillance System methodology to collect data on rare cases and to provide robust data on the potential impact of an increasing number of repeat CS procedures. As pointed out by Kamel et al., much work has been published on women undergoing their third CS, but there is relatively little information concerning women undergoing larger numbers of procedures. With the incidence of primary CS increasing, the numbers of women undergoing multiple repeated CS is also likely to increase. The potential impact of having multiple caesareans will therefore become extremely relevant to clinicians and women.
We agree that women undergoing their second CS may have a relatively lower surgical morbidity than those having their fifth or more procedure, and, indeed, it is this difference in morbidity and its impact on women and their babies that our study sought to quantify and describe. The ‘number of previous caesareans’ is not therefore a source of bias, but the defining feature of our cohort and comparison groups. We would also like to clarify that ‘Table 4. Maternal complications’ contains odds ratios which were adjusted for maternal age and smoking status.
Kamel et al., expressed concern that the skills and experience of the surgeons performing CS may have ‘biased’ our findings of increased surgical morbidity in the multiple repeat caesarean section (MRCS) group and, especially, the abnormal placentation subgroup (n = 17), which had a hysterectomy rate of nearly 50%; 78% of women in the MRCS group were operated on by consultants/associate specialists, compared with only 34% of women in our comparison group. Thus, the higher rates of morbidity described in the MRCS cohort occurred despite more experienced operators. This difference in operator experience may have helped to prevent some of the additional morbidity in the MRCS group, and thus led to an apparent underestimate of the difference between the two groups. Any potential bias would therefore operate in the opposite direction to that hypothesised by Kamel et al.; the differences we estimate are likely to be conservative estimates of the true difference on the basis of potential confounding by operator experience.
We agree that it is interesting that the MRCS group had a higher incidence of preterm delivery. Preterm deliveries occurred substantially in pregnancies complicated by placenta praevia or accreta, and we hypothesise that this may represent an iatrogenic response to antepartum haemorrhage in this very high-risk subgroup of women. Obstetricians may prefer to deliver such cases electively in ‘office hours’ with senior staff available, even at preterm gestations. Women in this subgroup should be counselled that early delivery is a possible consequence of placental abnormalities, and that this may have implications for their baby.