Introduction

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Despite decades of political and academic debate the relative merits of home versus hospital birth remain unproved. This is likely to remain so. Comparisons that are sufficiently unbiased and large enough to address crucial safety issues are unlikely to be forthcoming. ^{1 2} Although home and hospital offer different risks and benefits for births, neither has standard care characteristics. In fact the range from safe to unsafe practice may be wider within each location than it is between them. Addressing what constitutes safe birth practice at home may be a more pivotal concern than attempting to quantify the theoretical differences attributable to place of birth.

In the Netherlands, where 30% of births are planned to be at home, there is a widely accepted list of criteria for home birth.³ When home birth is uncommon, opinions and practice can vary more widely. Thus leaflets on informed choice of place of birth in the United Kingdom do not specify any contraindications to home birth. ^{4 5} Others have advocated home birth for women at high risk of obstetric complications, ^{6 7} and trends to abandon risk assessment for home birth are apparent in both Australia⁸ and the United States.⁹

We evaluated the outcomes of Australian home births and compared these with all Australian births and planned home births elsewhere.

	Subjects and methods

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Data on planned home births
A planned home birth was defined as a birth that, at the onset of labour, was intended to occur at home with the assistance of a home birth practitioner. This definition excluded antepartum transfers, unplanned home births, and births where the woman was supported only by family and friends. Home birth practitioners included midwives and medical practitioners, both registered and non-registered, but not Aboriginal traditional midwives.

Data on perinatal deaths
Australian perinatal death refers to stillbirth and death within 28 days after birth, of an infant weighing 500 g or more. This definition includes stillbirths and deaths within the first week and late neonatal deaths.

Data analysis and comparisons
Data on home births were compared with all Australian births during 1985-90 and with planned home births elsewhere, identified from a literature search for comparable data from the 1980s and 1990s. The CIA program was used for statistical analysis.¹⁰

	Results

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Perinatal deaths
Among the 7002 home births studied, there were 50 deaths (31 fetal and 19 neonatal) (table 1) giving a perinatal death rate of 7.1 per 1000 according to the Australian definition. Excluding the five late neonatal deaths gives a perinatal death rate of 6.4 per 1000 according to criteria of the World Health Organisation. Thirteen of the 31 stillbirths were born in hospital after transfer of the mother during labour, but at least 10 fetuses were dead on arrival in hospital. Three infants died during transfer to hospital, one before and two after birth. All but one of the 19 neonatal deaths occurred in infants born at home.

Asphyxial deaths
Three babies, weighing 4295 g, 4600 g, and 6020 g, died from non-anticipated shoulder dystocia; meconium had been noted during labour for two of them. Most other deaths from intrapartum asphyxia occurred in fetuses known to be at increased risk of perinatal asphyxia (table 2).

Comparison with Australian perinatal mortality
During 1985-90 there were just over 1.5 million births in Australia, giving a death rate (including late neonatal deaths) of 10.8 per 1000 compared with 7.1 per 1000 in planned home births (table 4). In the home birth population, however, severe pathology and very preterm pregnancies with the highest risk of mortality are underrepresented. ^{11 12} For example in home births with known birthweight, only 1.4% were of low birthweight. ^{11 12} Birthweight specific mortality was calculated only for the years with the most comprehensive data (1985-8). The death rate for infants weighing 2500 g in 1985-8 was 5.7 per 1000 in home births compared with 3.6 per 1000 nationally (relative risk 1.6; 95% confidence interval 1.1 to 2.4).

Comparison with home birth internationally
Comparison of data from reports on home births is hampered by large differences in definition and inclusion criteria. A search of the literature during the 1980s and 1990s identified seven studies with definitions and criteria that permitted comparison with the national Australian data. These studies were from Australasia, ^{13 14} Europe,^15-18 and the United States.¹⁹ Australian planned home births had a perinatal death rate about twice as high as these countries (table 5).

	Discussion

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Our analysis has shown cause for concern about some Australian home birth care. Firstly, the mortality is excessively high when considering that severe pregnancy disorders are grossly underrepresented in this population. ^{11 12} The only category known to be overrepresented is post-term pregnancy (10.7%). Secondly, in most countries the majority of deaths are preterm antepartum deaths and these are largely excluded by the definition of planned home birth. Thirdly, the intrapartum death rate among normally formed infants weighing 1000 g was three times higher than the national average. Fourthly, over half of all deaths were associated with intrapartum asphyxia. All these babies were born at home or if born in hospital were dead before arrival, while those referred after birth were all diagnosed with severe damage. Yet a large number were known to be at increased risk of intrapartum asphyxia before the onset of labour. Many of the deaths had been preceded by warning signs such as the presence of meconium and fetal bradycardia, in addition to pre-existing risks, without any action being taken or only too little, too late. The risk of death in such circumstances should not be underestimated, particularly as the capacity to care for severely asphyxiated babies at home is limited.

When compared with data on planned home birth in other industrialised countries, the perinatal death rate in Australia was much higher. There are several possible explanations for this. Firstly, our detection and ascertainment of deaths may have been better than it is elsewhere. Low participation in population based studies of planned home births is common. A national study from the United States for example achieved only a 67.6% response rate and surveyed registered midwives only.¹⁹

Secondly, Australian home birth practitioners might differ from home birth practitioners elsewhere. Home birth practice in Australia is nearly 100% private practice and characterised by low caseloads. On average during 1985-90, 53% of practitioners attended less than five home births a year, and only 13% attended more than 20 home births a year. ^{11 12} This contrasts with the Netherlands, for instance, where home midwifery caseloads of more than 100 births a year are common.¹⁶ It is not known, however, if practitioners in our study also practised in other settings.

Thirdly, our study also included unregistered midwives. However, comparatively few births were attended by unregistered practitioners alone (n=737) and these births did not have a high death rate (2.7 per 1000).

A fourth, and more compelling explanation, is that some home birth practitioners in Australia no longer offer home birth to women at low risk. At least 18 deaths (36%) in this study occurred in twins, post-term and preterm infants, and breech presentations, which would be contraindications for home birth elsewhere. Post-term births had a death rate twice that of other home births, and home birth mortality was 1 in 14 for breech presentation and 1 in 7 for twins. The two largest contributors to the excessive mortality were an underestimation of the risks of perinatal asphyxia in such births and, more generally, underestimation of the significance of fetal distress. This raises questions about other effects of prolonged asphyxia that were not addressed in this study.

We found only one other study, conducted in the United States, on mortality associated with breech, twin, and post-term births at home.⁹ This study showed excess mortality in such home births and voiced concern about the trend to encourage midwives to engage in high risk practice. We share that concern. Because of the well established risks and the lack of encouraging outcome data, such practice must be labelled as inadvisable and experimental with all ethical safeguards that pertain to clinical experimentation. Overintervention and lack of choice for women with high risk pregnancies, however, could well encourage some to choose home rather than hospital birth. In many Australian hospitals, women with breech presentation or twins, for example, would only be offered caesarean section.

Our study highlights the need for objective guidance on what constitutes safe practice for birth at home. Given the inadequacy of many national datasets, both in size and quality, such guidance must inevitably draw on international data to be valid and reliable. It may also require ongoing audit to detect patterns of avoidable problems. Australian women, like women elsewhere, will continue to choose to give birth at home. They and their infants are entitled to effective care and support in their choice.