Changing patterns of perinatal and infant mortality in Western Australia: implications for prevention

Abstract

Perinatal and infant mortality rates have fallen dramatically in the developed world this century. A review of perinatal and infant mortality in Western Australia from 1970 to 1981 was undertaken, to examine trends in birthweight-specific and cause-specific rates. The predominant causes of death are now congenital malformation, stillbirth of unknown cause, preterm birth and cot death. Perinatal and infant mortality rates are unlikely to be reduced substantially until the reasons for these four causes of death are elucidated.

PIP: Stillbirth, neonatal, and postneonatal infant deaths in Western Australia were analyzed from 1970 to 1981. Falls in all 3 rates were apparent. The neonatal mortality rate showed the sharpest decline, from 14.05 to 5.47/1000 total births. The stillbirth rate dropped from 12.64 to 8.31, and the postneonatal infant mortality rate fell from 6.24 to 2.27. The intrapartum stillbirth rate for nonmalformed fetuses of over 28 weeks gestation fell from 2.55 in 1970 to 0.68 in 1981. The largest percentage of stillbirths, 37% in both 1970 and 1981, was associated with birthweight under 1000 gm. Congenital malformation as a cause of neonatal death doubled from 20.9% in 1970 to 39.2% in 1981. In the postneonatal period, crib death accounted for 35.2% of deaths in 1970 and 51.9% in 1981. Recent improvements in perinatal and infant mortality are attributed to better obstetric and pediatric services as well as the introduction of neonatal intensive care units. 4 conclusions are drawn from these findings: 1) the major causes of perinatal and infant deaths--congenital malformations, stillbirths of unknown cause, preterm births, and crib death--should be investigated further; 2) given the current low levels of mortality, further improvements in health care cannot be expected to generate additional dramatic declines, and the task is to develop indices of perinatal morbidity as measures of care and to identify problem areas; 3) prevention of preterm births and malformation has the potential to reduce both morbidity and mortality; and 4) declines in community-based factors such as standard of living, immunization coverage, and access to medical care are certain to have a negative effect on infant mortality rates.