Once a Caesar . . .
Another frequently cited reason for shunning a CS is to avoid another one for a later pregnancy. There's an old medical maxim that says 'Once a Caesar, always a Caesar' as, traditionally, it is believed thata CS scar weakens the mother's abdomen, and so makes it more vulnerable to the pressure of a subsequent normal delivery.

This so-called VBAC (vaginal birth after caesarean) issue remains a hotly debated topic in obstetric circles. In the US, for example, over 300 hospitals have reportedly now banned VBACs over fears of malpractice suits. As a result, VBAC rates have plummeted. However, that trend is being challenged by a few vociferous American women pressure groups. They claim that doctors who insist on repeat CSs are denying women the right to have a natural birth-which in any case, they say, is just as safe as a caesarean.

Which side is right? Unfor-tunately, no one really knows. Two exhaustive reviews of the clinical data, one going back as far as 40 years, have proved inconclusive, partly because good-quality data are lacking (Aust NZ J Obstet Gynaecol, 2004; 44: 387-91; Oregon Health & Science University Publication No 03-E018, March 2003). An older study of more than 5000 deliveries found not one maternal death (Obstet Gynaecol, 1982; 59: 135).

Breech births
There is, however, one aspect of the CS issue where there's some-what broader agreement. If labour is difficult and the life of the mother or child is immediately under threat, an emergency caesarean is generally considered the safest option.

The most common emergency situation is with so-called breech births-where the baby has its bottom facing the birth canal rather than being head downwards. In the days before anesthesia and surgery, all manner of complex devices were invented to extract the baby from this difficult position-one that is potentially dangerous to both the mother and infant. Some doctors have also attempted to solve the problem by developing techniques of turning the baby in the womb from the outside. More recently, the trend in these cases has been to perform a CS rather than risk a natural delivery.

But here again, this issue has divided the world of obstetrics, with some arguing passionately that CS is not necessarily the safer option for breech-presenting babies.

In an effort to resolve the controversy, Canadian researchers set up a huge international trial, involving over 2000 breech births in 121 maternity units around the world. Roughly half of the babies were delivered naturally, with the other half by CS. Although the absolute risks to the infants were relatively small in both cases, the differences appeared to be clear-cut: whereas 1.6 per cent of the breech babies either died or were damaged by the CS operation, that figure leapt to 5 per cent for those born without it. In both scenarios, the mothers fared equally well (Lancet, 2000; 356: 1375-83).

This result should have meant 'case closed' in favour of CS for breech deliveries-but not so. A few years later, South African researchers collated fresh inter-national birth data which showed that the benefit of CS to the infant had to be weighed against a modest increase in danger to the mother (Cochrane Database Syst Rev, 2003; 3: CD000166).

This revised stance was again confirmed by Dutch doctors who agreed that CS was better for the child, but not necessarily for the mother (Br J Obstet Gynaecol, 2003; 110: 604-9).