A comparison of the Perinatal Society of Australia and New Zealand-Perinatal Death Classification system and relevant condition at death stillbirth classification systems.

BACKGROUND

Stillbirths comprise two-thirds of all perinatal mortality. A classification system with low 'unexplained' stillbirth rates is important when developing prevention strategies.

AIMS: This study aims to (i) determine whether the proportion of stillbirths classified as 'unexplained' is reduced, by using the relevant condition at death (ReCoDe) stillbirth classification system, compared with the Perinatal Society of Australia and New Zealand - Perinatal Death Classification (PSANZ-PDC) system; and (ii) compare the proportion of stillbirths attributed to fetal growth restriction and other causes by each system.

METHODS

The ReCoDe stillbirth classification system was applied to the National Women's Health's stillbirth database for years 2004-2007. The proportion of stillbirths classified as 'unexplained' and as a result of fetal growth restriction was compared between the ReCoDe and the PSANZ-PDC systems using the chi(2) test.

RESULTS

The proportion of stillbirths classified as unexplained was less with ReCoDe compared with PSANZ-PDC (8.5% (n = 26) vs 14.1% (n = 43) P = 0.04). The proportion with the primary cause attributed to fetal growth restriction was increased with ReCoDe compared with PSANZ-PDC (23.2% (n = 71) vs 8.2% (n = 25) P < 0.0001). However, 44.8% (n = 137) of all stillbirths were small for gestational age (birthweight < 10th customised centile). The most common primary cause or condition at death by both systems was congenital abnormalities.

CONCLUSION

The proportion of stillbirths classified as unexplained was less with ReCoDe compared with PSANZ-PDC but rates with either method were low compared with earlier classification systems. Fetal growth restriction was listed as the primary condition more commonly with ReCoDe compared with PSANZ-PDC because of different definitions.