Maternal mortality and psychiatric morbidity in the perinatal period: challenges and opportunities for prevention in the Australian setting

The assessment of maternal deaths relating to psychiatric morbidity in the perinatal period poses several challenges: the definition and classification of maternal deaths, the difficulty of detecting all maternal deaths, and the definition of psychiatric morbidity and mortality in the maternity setting.

“Maternal deaths” were traditionally defined as occurring any time during pregnancy and up to 42 days postpartum, with additional classification as “direct”, “indirect” or “incidental”.1 Direct deaths result from obstetric complications (eg, eclampsia). Indirect deaths result from a condition that is not directly related to obstetric causes but is aggravated by the effects of pregnancy (eg, a cardiac condition).1 In Australia, before 1997, deaths from psychiatric illness, apart from puerperal psychosis (which was classified as a direct cause), were classified as incidental maternal deaths (conditions occurring during pregnancy but for which the pregnancy is unlikely to have contributed significantly to the death). In line with recommendations from the 1997–1999 Confidential Enquiries into Maternal Deaths in the United Kingdom (the “National Institute for Clinical Excellence [NICE] report”),2 Australia has classified these deaths as indirect since the 1997–1999 triennium.

More recently, the classification of maternal deaths was broadened (ICD-10 coding) to include late maternal deaths — that is, deaths from direct or indirect causes between 43 and 365 days postpartum.1 Deaths associated with psychiatric illness are increasingly being included in the category of late maternal deaths.

It is well recognised that maternal deaths due to psychiatric illness have been under-reported, partly because of misclassification of suicides as incidental deaths, and partly because of under-reporting of late maternal deaths.3 Late maternal deaths are more difficult to identify, as they often occur after women have ceased to attend maternity services. Researching deaths thereafter is reliant on various data collections (including coroners’ reports and state registries of births, deaths and marriages), which in the past have not necessarily identified death in relation to giving birth, thus making them a less reliable source of information. In Australia, this problem is now being addressed by the inclusion of an item on death certificates enquiring about pregnancy in the preceding year and the incorporation of ICD-10 coding into coroners’ reports.

Where linkage studies of death and birth data have been performed, they have revealed an over-representation of maternal deaths associated with suicide or psychiatric illness. Many of these deaths are not captured by routine data collection methods because they often occur after 42 days postpartum.3,4 Thus, an Office of National Statistics (ONS) linkage study in the UK identified over 40 extra maternal deaths in the 1997–1999 triennium from suicide or violent causes, making suicide the leading cause of indirect maternal deaths once these cases were added to the NICE report statistics.5,6 The ONS study demonstrated that 65% of all maternal suicides were not included in the NICE report, due mainly to the lack of reporting of late indirect maternal deaths.5 A similar finding was also demonstrated in a Finnish linkage study of maternal deaths,7 which reported 73 suicides associated with pregnancy between 1987 and 1994. A pilot data linkage study is underway to investigate the coverage and quality of maternal death data collections in Australia and the extent of ascertainment bias.

From the psychiatric perspective, there has also been a conceptual shift. Researchers and clinicians have moved away from focusing solely on postnatal psychiatric disorders to including disorders arising across the perinatal period. In the mental health context, the perinatal period is usually defined as encompassing pregnancy through to the end of the first year postpartum.8

In Australia, identifying psychiatric disorders in the maternity setting presents researchers with a further methodological challenge. As detailed mental health reports are not available to the state and territory maternal mortality committees, it is difficult to establish, in some cases, whether a woman has experienced a psychiatric disorder. For the purposes of this article, we have defined “psychiatric disorder” as either probable current mood disorder or psychosis, or a past history of mental health problems, or past or current contact with psychiatric services.

Finally, as confirmation of death by suicide is always difficult, we have focused instead on maternal death associated with psychiatric morbidity (including suicide and deaths related to substance misuse).

Data on maternal deaths in Australia are provided to the National Perinatal Statistics Unit by state and territory maternal mortality committees. These committees receive death notifications from medical practitioners, midwives, hospitals, health departments, and coronial and postmortem investigations. Health departments also interrogate perinatal and hospital morbidity data collections and death data from state registries of births, deaths and marriages. Individual maternal mortality committees are responsible for conducting confidential death enquiries that assign each death a principal cause and classification.

Our report focuses on deaths extracted from reports on maternal deaths in Australia between 1994 and 2002.9-11 Twenty-six deaths associated with psychiatric causes occurred over this period (Box 1). Of these, 17 (65%) occurred antenatally, with 13 (76%) of these occurring at less than 20 weeks’ gestation. Six of the nine postnatal deaths occurred in the 42 days after birth. Ten women hanged themselves, and there was an increase in deaths due to hanging across the three triennial periods examined between 1994 and 2002. Another seven women died from other violent causes: gunshot wounds, drowning, intentional road trauma, jumping or poisoning. In total, 17 women (65%) died violently, suggesting a profound wish to die. The other nine women died from an overdose of prescription or illicit drugs.

Of the 13 women experiencing a psychiatric episode at the time of death, nine suffered from anxiety or depressive disorder and four from a severe psychiatric disorder (bipolar disorder [2], schizophrenia [1], and psychotic depression [1]). A further six women had a past history of depression (three had had postnatal depression), and in seven cases the diagnosis was unknown. Thus, 19 women (73%) had a previous or current psychiatric disorder.

Five of the 26 women had received medication for psychiatric conditions during pregnancy, as reported to the Australian Institute of Health and Welfare National Advisory Committee on Maternal Mortality. All five had stopped taking their medications: two were concerned about the potential effect on their babies, one stopped because of side effects, another for an unknown reason, and one had a long history of psychiatric illness and regularly ceasing medication. Six women had been inpatients in a psychiatric institution during the pregnancy or after the birth, suggesting severe psychiatric illness.