Postneonatal mortality in south New Zealand: necropsy data review

Abstract
Summary. Three southern New Zealand health districts had a postneonatal mortality rate of 8.1 per 1000 livebirths and a postneonatal sudden infant death syndrome (SIDS) mortality rate of 6.3 per 1000 livebirths for the period 1979–1984. This is one of the highest reported rates of SIDS. The 429 postneonatal deaths occurring during the period were assigned to one of four groups: unpreventable (n= 52), possibly preventable non‐SIDS (n= 45), SIDS with minor abnormalities at necropsy or premorbid symptoms (n= 167), and SIDS with no abnormalities at necropsy or documented premorbid symptoms (n= 165). These groups were related to obstetric and perinatal data. For those infants classified as SIDS, the winter peak of deaths was particularly marked if death occurred after 3 months of age. These older SIDS deaths had more minor abnormalities at necropsy, a longer interval between time last seen or heard alive and found dead and more thymic petechiae.