KEY POINTS:
Caesareans are likely to be the commonest way of delivering a baby at Auckland City Hospital within five years, a report says.
The 2006 clinical report of the hospital's National Women's service shows that 33.1 per cent of births at the facility were caesareans - nearly twice the rate for 1991. Just over half of all births were spontaneous vaginal deliveries last year, down from 68 per cent in 1991.
"Although the majority of births are still spontaneous vaginal," the report says, "at current trajectory, the lines would be expected to cross in about five years."
Vaginal deliveries using forceps or other instruments have remained stable at 12 to 14 per cent for 15 years.
The reasons for the continuing increases in the caesarean rate are not clear, but it is thought to be related to increases in the average age of child-bearing and obesity.
The report says the rate of elective caesareans, which comprised more than a third of all caesareans at National Women's, increased markedly with maternal age.
It says it is of concern that even among low-risk cases - women who have not had a caesarean, who are having a second or subsequent single baby, whose head is pointing down, and in a spontaneous labour - the caesarean rate has increased sharply in the past decade.
The proportion of women aged 36 to 40 giving birth has more than doubled since 1991, to more than 20 per cent last year.
"The most common age category among women having their first and later babies is now 31-35 years rather than the 26-30 years seen previously."
The hospital has recently begun an audit of caesareans, focusing on the leading reasons for them, including failure of labour to progress. This accounted for 26 per cent last year, followed by having had a previous caesarean (22 per cent) and fetal distress (16 per cent). Maternal request accounted for 6 per cent.
The report also charts an increase in women who haemorrhaged more than a litre of blood following birth, "which is in part due to the increased caesarean section rate".
Clinical services general manager Kay Hyman said the hospital monitored its caesarean rate, but was "no more concerned now about this trend than we have been previously".
The Waitemata District Health Board's clinical director of obstetrics, Dr Sue Belgrave, said its caesarean rate was 26 per cent last year and had been 24 to 26 per cent for several years.
She said rising caesarean rates were closely related to increasing maternal age.
"Lots of obstetric complications increase as we get older."
Maternity Services Consumer Council coordinator Lynda Williams was shocked by the prospect of caesareans becoming the dominant form of birth at the hospital, as they had significantly increased risks of complications and death.
"I don't think women are being given good information about the risks involved, not only for them but for their babies, in having a caesarean."
Caesarean births
* Total of 7212 births last year at National Women's.
* 33.1 per cent were caesareans, against 16.6 per cent in 1991.
* 20.3 per cent of births last year were emergency caesareans and 12.8 per cent were elective caesareans.
* Waitemata District Health Board's caesarean rate last year was 26 per cent.
* The national rate was 23.7 per cent in 2004.
* Australia's rate in 2002 was 29.4 per cent.
