Doctors in the US are taking another look at medically-managed childbirth, as the number of births scheduled for convenience rises. Fewer than 10% of women underwent induction in 1990, but more than 21% in 2004. Similarly, the rates of caesarean section rose from 23% to 29%. Estimates of the number of inductions for convenience range from 15% to 55% of the total. "People want to schedule their birth like they schedule their nail appointments," says Janie Wilson, of Intermountain Healthcare. For several years her organisation, which runs hospitals in Utah and Idaho, has been trying to reduce the number of elective inductions.

The problem is that the practice creates unnecessary risks and costs: more C-sections, more use of forceps and vacuum devices, longer hospital stays and sometimes, more painful labour. Admittedly, there is little evidence that elective induction causes long-term harm to the mother or baby.

Induced births are convenient for doctors, too -- another reason why they are being criticised. A recent study in the Annals of Family Medicine suggested that "preventive labour induction" may produce the best safety options. However, Dr Michael C. Klein, of the University of British Columbia, wrote a critical editorial in response. "This is another study saying to women, "you can't survive without us making things better; nature is completely off-track. And there is a huge reservoir of practitioners out there who want to hear this message.