The nationwide study, of 2,400 mothers reported wide geographical discrepancies in Caesarean rates which, the commission said, indicated that some doctors were too quick to rely on this method.
Women who had interventions during childbirth, including forceps deliveries and Caesareans, described "reduced levels of satisfaction and confidence", felt "less well supported and suffered increased postnatal ill health," according to the report.
"There is general consensus that levels of Caesarean section are higher than are clinically required ... Caesarean sections at trusts visited ranged from 11 per cent to 18 per cent of deliveries and vary more than twofold nationally [the average being 17 per cent]," the report said.
Obstetricians perform Caesarean sections for a variety of reasons, including abnormal foetal presentation, foetal distress and poor progress during labour.
The report said: "These interventions have important consequences, with women taking longer to recover and staying longer in hospital, making them more costly. A Caesarean section can cost in excess of pounds 700".
The Audit Commission collected information from 13 NHS trusts, 12 commissioning authorities and 300 GPs, as well as from women who had given birth in June and July 1995.
Each year the NHS spends more than pounds 1.1bn on maternity services for about 650,000 women, at a cost of about pounds 1,700 per delivery. The commission found that many trusts provided more antenatal check-ups than were needed for low-risk women and some relied too much on specialist involvement.
This was more expensive and less popular than local community services provided by midwives and GPs, and tied up resources worth pounds 10m annually, which could be better spent on providing better information to women, said the report.
Although health authorities and trusts have been encouraged to take a more woman-centred approach, since the publication of Changing Childbirth by the government-appointed Expert Maternity Group in 1993, the commission says that they could do more.
In many ways, the report is an indictment of the hospital services, showing that less than half of pregnant women felt that hospital staff gave them confidence and less than two in five felt that someone got to know them. One in four women reported being left alone in labour, at a time that worried them.
Ms Beverley Fitzsimons, project manager at the commission, said: "Health authorities have got to use a variety of means to find out what women want, including consulting local maternity services liaison committees. "We found the general growth in Caesarean sections worrying, and the variation between trusts worrying. We do not believe that there is such a thing as "a correct rate", but a rate which is right for the particular case- mix. We would recommend that each trust reviews its Caesarean rate to see whether it is justified."
Postnatal hospital care came in for the most critical comment, with women complaining about "poor food and hygiene, cramped bathrooms and inadequate eating areas." They also felt that different professionals gave them conflicting advice on breast feeding.