Throwing the baby out with the spa water?

To the Editor: In a recent article, de Costa and Robson1 suggest that Australia’s high rates of caesarean surgery — currently among the highest in the Western world — may be beneficial, and causally related to our low perinatal mortality rate.

In support, they cite a single article that reports the outcomes from three large hospitals in Dublin between 1979 and 2000.2 In these hospitals, as in most of the Western world, caesarean rates increased and perinatal mortality rates declined over this 21-year period. The authors of the article ascribe a causal relationship, but admit that “. . . it was not possible to allow for the confounding effect of time”.2 The time factor also confounds the interpretation of Australian data.

Furthermore, results from an earlier Dublin study “. . . do not support the contention that the expansion in cesarean birth rates has contributed significantly to reduced perinatal mortality in recent years,”3 and there are many other articles with similar conclusions.4

Moreover, de Costa and Robson do not acknowledge the significant morbidity associated with caesarean surgery, nor the risks to mother and baby in subsequent pregnancies. A recent large retrospective cohort study in Scotland found that women whose first baby had been born by caesarean section had twice the risk of unexplained stillbirth at term in the subsequent pregnancy.5 There are also well documented increased risks of placental pathology (placenta praevia, accreta and percreta) in this group. Such problems are likely to increase in Australia in proportion to the increase in caesarean rate.

I note also that King et al, who discuss maternal mortality in the same issue of the Journal, specifically mention the contribution of previous caesarean surgery to severe obstetric haemorrhage and emergency hysterectomy.6 They report that maternal death from amniotic fluid embolism occurred in association with induction in five of seven cases. Australian rates of induction and augmentation are among the highest in the Western world.

Finally, as regards onus of proof, I agree with the statements by Enkin et al7 that “. . . the only justification for practices that restrict a woman’s autonomy, her freedom of choice, and her access to her baby, would be clear evidence that these restrictive practices do more good than harm; and second, that any interference with the natural processes of pregnancy and childbirth should also be shown to do more good than harm”, and “. . . the onus of proof rests on those who advocate any intervention that interferes with either of these principles”.