Perinatal mortality disparities between public care and private obstetrician-led care: a propensity score analysis

Abstract

Objective: To examine whether disparities in stillbirth, and neonatal and perinatal mortality rates, between public and private hospitals are the result of differences in population characteristics and/or clinical practices.

Design: Retrospective cohort study.

Setting: A metropolitan tertiary centre encompassing public and private hospitals. Women accessed care from either a private obstetrician or from public models of care - predominantly midwife-led care or care shared between midwives, general practitioners, and obstetricians.

Population: A total of 131 436 births during 1998-2013: 69 037 public and 62 399 private.

Methods: Propensity score matching was used to select equal-sized public and private cohorts with similar characteristics. Logistic regression analysis was then used to explore the impact of public-private differences in the use of assisted reproductive technologies, plurality, major congenital anomalies, birth method, and gestational age.

Main outcome measures: Stillbirth, and neonatal and perinatal mortality rates.

Results: After controlling for maternal and pregnancy factors, perinatal mortality rates were higher in the public than in the private cohort (adjusted odds ratio, aOR 1.53; 95% confidence interval, 95% CI 1.29-1.80; stillbirth aOR 1.56, 95% CI 1.26-1.94; neonatal death aOR 1.48, 95% CI 1.15-1.89). These disparities reduced by 15.7, 20.5, and 19.6%, respectively, after adjusting for major congenital anomalies, birth method, and gestational age.

Conclusions: Perinatal mortality occurred more often among public than private births, and this disparity was not explained by population differences. Differences in clinical practices seem to be partly responsible. The impact of differences in clinical practices on maternal and neonatal morbidity was not examined. Further research is required.

Tweetable abstract: Private obstetrician-led care: more obstetric intervention and earlier births reduce perinatal mortality.

Plain language summary: Background Babies born in Australian public hospitals tend to die more often than those born in private hospitals. Our aim was to determine whether this pattern is a result of public-private differences in care or merely linked with differences in the characteristics of the two groups. In Australian private hospitals, a private obstetrician almost always provides continuing care to each woman during pregnancy and birth. Public hospitals provide a number of care options, which usually involve midwives and/or a family doctor. Method The study population included 131 436 births (52.5% public; 47.5% private) from 1998-2013 at a single metropolitan centre with co-located public and private facilities. To isolate the effect of differences in care, we used a statistical technique called propensity score matching to select a public group and a private group with similar characteristics and equal size. This enabled us to compare 'apples with apples' when comparing public versus private perinatal death rates. Perinatal deaths include stillbirths and babies that die within 28 days of birth. Main findings After matching and after accounting for different patterns in the use of fertility treatments and multiple-birth pregnancies (such as twins), babies born in the public sector were approximately 1.5 times more likely to die than babies born in the private sector. This difference was reduced to 1.3 times more likely to die than babies born in the private sector after taking into account other factors that could skew the data, such as major congenital anomalies, birth method, and duration of pregnancy. Limitations This was a single-centre study, so the results may not apply to all settings. Despite our efforts to create highly similar public and private cohorts, some differences between the groups are likely to have remained and this may have affected the results. Implications Our findings suggest that private obstetrician-led care has a beneficial impact on perinatal deaths, despite, or possibly because of, higher obstetric intervention rates and earlier births in the private hospital. Further research is required.

Keywords: Hospital sector; neonatal death; perinatal mortality; propensity score; stillbirth.