Rates for obstetric intervention among private and public patients in Australia: population based descriptive study

British Medical Journal, July 15, 2000 by Christine L Roberts, Sally Tracy, Brian Peat

Abstract

Objective To compare the risk profile of women receiving public and private obstetric care and to compare the rates of obstetric intervention among women at low risk in these groups.

Design Population based descriptive study.

Setting New South Wales, Australia.

Subjects All 171 157 women having a live baby during 1996 and 1997.

Interventions Epidural, augmentation or induction of labour, episiotomy, and births by forceps, vacuum, or caesarean section.

Main outcome measures Risk profile of public and private patients, intervention rates, and the accumulation of interventions by both patient and hospital classification (public or private).

Results Overall, the frequency of women classified as low risk was similar (48%) among those choosing private obstetric care and those receiving standard care in a public hospital. Among low risk women, rates of obstetric intervention were highest in private patients in private hospitals, lowest in public patients, and generally intermediate for private patients in public hospitals. Among primiparas at low risk, 34% of private patients in private hospitals had a forceps or vacuum delivery compared with 17% of public patients. For multiparas the rates were 8% and 3% respectively. Private patients were significantly more likely to have interventions before birth (epidural, induction or augmentation) but this alone did not account for the increased interventions at birth, particularly the high rates of instrumental births.

Conclusions Public patients have a lower chance of an instrumental delivery. Women should have equal access to quality maternity services, but information on the outcomes associated with the various models of care may influence their choices.

Introduction

Caesarean sections have been widely scrutinised, without consideration of other obstetric interventions.[1-4] A recent Australian parliamentary inquiry, with a mandate to explore the differences between public and private care, heard repeated submissions that high caesarean rates in the private sector are probably because large numbers of women at high risk take out private health insurance for pregnancy care.[4] However, there are no data to support this assertion and neither is there information about other obstetric interventions associated with medical insurance status. International comparisons show Australia to have among the highest rates for obstetric intervention; in 1996, 20% of women had caesarean sections and 11% had instrumental births.[5 6]

Australian maternity care has features of British and American systems; all women are covered by national health insurance, which provides free maternity care for patients in public hospitals (public patients), but about one third take out private medical insurance or pay for private obstetric care (private patients). For private patients, antenatal care is provided in private rooms by an obstetrician chosen by the woman, and delivery may be at either a private or a public hospital. Public patients receive antenatal care and birth care at public hospitals, and care is provided by rostered midwives, residents, registrars, and staff obstetricians. Women choose their care depending on their knowledge of what is available, whether or not they can meet the costs of private insurance or private care, and their proximity to services.[7]

We aimed to compare the risk profiles of women receiving public and private obstetric care and to compare the rates of obstetric intervention among women at low risk in these groups giving birth in New South Wales, Australia.

Subjects and methods

The study population comprised women delivering a live infant in New South Wales from 1 January 1996 to 31 December 1997. Data were obtained from the NSW Midwives Data Collection, a population based surveillance system covering all births in New South Wales, which relies on midwives to record information on each birth.[8 9] We compared maternal demographic and clinical factors among public and private patients. Maternal factors available for analysis were age, parity, medical conditions (any or none reported, including pre-existing diabetes mellitus and essential hypertension), and obstetric complications (any or none reported, including antepartum haemorrhage, pregnancy induced hypertension, gestational diabetes, and rupture of membranes before labour). Type of labour was classified as spontaneous, augmented, induced, or none (caesarean section before labour). Augmented and induced labours were those where drugs were used to augment or induce labour. Other factors for management of labour were type of delivery (vaginal, vacuum, forceps, or caesarean section), epidural, episiotomy, and third degree tear. Infant factors available for analysis were presentation, multiple birth, gestational age, birth weight, birthweight percentile,[10] and Apgar score at five minutes.

We considered women to be at low risk of poor pregnancy outcome if they were aged 20-34 years with no medical or obstetric complications and a singleton of normal size (10th-90th birthweight percentile) presenting in the cephalic position and born at term (37-41 weeks' gestation). Primiparas (first birth at 20 weeks or more of gestation) were examined separately from multiparas (previous births) because of the significant impact of the care and outcome of previous pregnancies on care in multiparous pregnancies.