Timing, causes and investigation of perinatal deaths

Timing of perinatal deaths

In 2017, where the timing of perinatal deaths was stated:

  • The majority (83.5%) of stillbirths occurred before the onset of labour (antepartum death)
  • Three in five (60.4%) neonatal deaths occurred within the first 24 hours following birth and were more common with decreasing gestational age
  • Early neonatal deaths (1–7 days) and late neonatal deaths (8–28 days) were more common among babies born from 36 weeks gestation.

Definitions of timing of perinatal death can be found in the Technical notes—Definitions used in reporting.

Intrapartum stillbirths (those occurring during labour and birth) and neonatal deaths within the first 24 hours after birth are often considered together as, in many cases, the process leading to the death is a continuum that may lead to death before or after the birth occurs.

Timing of perinatal deaths, 2017 

The vertical bar chart at the top of this data visualisation shows the timing of perinatal deaths. The majority, 60.8%, were antepartum stillbirths. This was followed by deaths in the very early neonatal period (less than 24 hours), and intrapartum stillbirths, 17% and 13.2% respectively. Early and late neonatal deaths accounted for less than 10% of deaths. 

The stacked horizontal bar chart at the bottom of this data visualisation shows the timing of perinatal deaths by gestational age group. Antepartum stillbirth was the most common time of death for all gestational age groups. Intrapartum stillbirth and very early neonatal death were more common in babies born at 20-22 weeks gestation, while early and late neonatal death were more common in babies born at 36 weeks gestation or more.

Causes of perinatal deaths

Causes of perinatal deaths are classified according to the Perinatal Society of Australia and New Zealand (PSANZ) Perinatal Mortality Classification System, version 2.2, as part of each state or territory’s perinatal mortality review process.

The PSANZ Perinatal Mortality Classification System incorporates a Perinatal Death Classification (PSANZ-PDC) and an additional Neonatal Death Classification (PSANZ-NDC).

The PSANZ-PDC system classifies all perinatal deaths (stillbirths and neonatal deaths) by the single most important factor which led to the chain of events which resulted in the death (refer to Technical notes—Definitions used in reporting for cause of death classifications).

In 2017:

The most commonly classified causes for all perinatal deaths were:

  • Congenital anomaly (31.9%)
  • Spontaneous preterm birth (15.2%)
  • Unexplained antepartum death (11.8%).

The most commonly classified causes of stillbirths were:

  • Congenital anomaly (32.6%)
  • Unexplained antepartum death (15.8%)
  • Maternal conditions (11.0%).

The most commonly classified causes of neonatal deaths were:

  • Spontaneous preterm birth (32.6%)
  • Congenital anomaly (30.0%)
  • Antepartum haemorrhage (9.0%).

The horizontal bar chart in this data visualisation shows that congenital anomaly was the most commonly classified cause of perinatal death, followed by spontaneous preterm birth and unexplained antepartum death.

In 2017, congenital anomaly was the most commonly classified cause of perinatal death, and this remained true across almost all deaths, regardless of maternal or gestational age, plurality, baby’s birthweight percentile or the timing of death. The only exceptions to this were for:

  • Babies born to mothers aged under 20. Maternal conditions were the most commonly classified cause of perinatal death for babies born to mothers under 20 (24.7%). Maternal conditions refers to deaths where a medical condition (e.g. diabetes) or a surgical condition (e.g. appendicitis) or an injury in the mother (including complications or treatment of that condition) is the cause.
  • Multiple births. Specific perinatal conditions, such as cord entanglement, were the most commonly classified cause for multiples (34.1%).
  • Late neonatal deaths (8–28 days). The most commonly classified cause of late neonatal deaths was spontaneous preterm birth (28.2%), followed by congenital anomaly (16.7%).
  • Neonatal deaths in babies not considered small for gestational age. Spontaneous preterm birth was the main classified cause of neonatal deaths for babies considered either appropriate or large birthweight for their gestational age (36.2% and 34.0%, respectively).

Additional causes of neonatal deaths

The PSANZ-NDC is an additional classification system applied only to neonatal deaths to identify the single most significant condition present in the baby in the neonatal period, the time from birth to 28 days, which caused the death.

In 2017, the most commonly classified conditions causing neonatal deaths were:

  • Extreme prematurity (34.8%)
  • Congenital anomaly (30.0%)
  • Neurological conditions (13.2%).

PSANZ-NDC cause of neonatal deaths, 2017

The horizontal bar chart in this data visualisation shows that extreme prematurity was the most commonly classified condition causing neonatal death, followed by congenital anomaly and neurological conditions.

Investigation following perinatal death

Autopsy

The National Perinatal Mortality Data Collection collects data on whether or not an autopsy was performed and, where applicable, the type of autopsy performed (a full autopsy, limited autopsy or external examination). For the purposes of this report, deaths where any of these autopsy types have been performed will collectively be treated as deaths where an ‘autopsy’ has been performed.

The purpose of an autopsy is to accurately identify the cause(s) of death. Autopsy results contribute to clinical audit and assist with identification of factors contributing to the death. Perinatal autopsy examinations require written consent from the parent(s) following informed discussion.

In 2017, there were 2,924 perinatal deaths, 2,040 of which (1,525 stillbirths and 515 neonatal deaths) had a stated autopsy status. Of deaths where autopsy status was stated, there were:

  • 874 (42.8%) perinatal deaths that had an autopsy performed
  • 711 (46.6%) stillbirths and 163 (31.7%) neonatal deaths that had an autopsy performed.

Autopsy of perinatal deaths, 2017

The bar charts show that more than half of all perinatal deaths reported not having an autopsy performed. A higher proportion of stillbirths reported having an autopsy performed than neonatal deaths, 46.6% vs 31.7% respectively.