To describe the pattern of stillbirths by cause and gestation period in New South Wales since the introduction of the Perinatal Society of Australia and New Zealand perinatal death classification (PSANZ-PDC); and to assess the agreement between classifications on cause of death between local hospital committees and the Perinatal Outcomes Working Party (POWP — a subgroup of the NSW Department of Health Ministerial Maternal and Perinatal Committee).

Population-based retrospective cohort study of all 258 045 births in NSW and all 1264 stillbirths classified by the POWP in 2002–2004, based on linked data on perinatal deaths from the NSW Midwives Data Collection and the NSW Ministerial Maternal and Perinatal Committee.

Pattern of stillbirths by cause and gestation period; and interobserver agreement on classification of cause of death (according to the PSANZ-PDC) between local hospital review committees and the POWP.

The most common classification was unexplained antepartum death, comprising 41.5% of the cohort and 60% of stillbirths of ≥ 37 weeks’ gestation. These unexplained stillbirths were more likely to have had an autopsy performed than the explained stillbirths (45% v 36%; χ2 = 10.1; df = 1; P = 0.001). Agreement on cause of death differed by cause of death classification, with an overall κ statistic of 0.638.

Unexplained antepartum death is the most common classification of stillbirths near term, and these stillbirths are more likely to have had an autopsy. Although reported interobserver agreement is high for PSANZ-PDC, in practice it is relatively low between hospital mortality review committees and the POWP.