Trends in caesarean section in Western Australia, 1980-1987.

During the 1980s the incidence of both emergency and elective caesarean section in Western Australia increased, accompanied by a decrease in that of all other delivery methods. The proportion of emergency caesarean sections increased from 5.9%. of all deliveries in 1980 to 8.2% in 1987 and that of elective sections from 5.3% to 8.7%. For each year studied less than 50% of primiparous women delivering singletons had a normal vaginal delivery. Emergency caesarean sections were more common in primiparas and at the teaching hospital and elective sections in multiparas and at the metropolitan private hospitals. The proportion of primiparas having either emergency or elective caesarean sections rose with maternal age, but for multiparas the proportion having elective sections rose, but there were few differences in emergency sections with increasing age. Repeat caesarean sections, which made up 28.8% of the total in 1987, have contributed increasingly to the rising proportion of caesarean section deliveries. Unless the number of emergency sections in primiparous women falls and the challenge of vaginal birth after caesarean section is met, it is likely that the caesarean section rate in Western Australia will continue to increase over the next decade.

Stillbirths in Western Australia 1980-1983: influence of race, residence and place of birth.

All stillbirths in Western Australia from 1980-83 weighing 1,000 g and over were identified from perinatal death certificates, and their causes and demographic correlates described. The stillbirth rate was 4.91 per 1,000 total births; nearly 65% were antepartum, 25% intrapartum and in 10% the time of death was unknown. The cause of death of most stillbirths was unknown (52%) or associated with lethal congenital malformations (13%), antepartum haemorrhage (12%) or maternal hypertension (8%). Whilst Aboriginal women had much higher stillbirth rates (10.80) than non-Aboriginal women (4.57), their patterns of time and causes of death were similar. Both antepartum and intrapartum stillbirth rates were much higher at low birth-weights and low gestational ages in both racial groups. Women living in rural areas who delivered in the metropolitan area had much higher antepartum (11.02) and intrapartum (3.31) stillbirth rates than either rural women delivering in rural areas (1.89 and 1.34) or metropolitan women delivering in the metropolitan area (2.72, 0.98). This reflects the transfer of rural high risk pregnant women or those with fetal death in utero, for delivery in metropolitan specialist hospitals.

Variation in hospital morbidity in the male workforce of Western Australia.

The associations of hospital morbidity with occupation were studied in Western Australian men of working age in 1981-2. Data on hospital morbidity were derived from a population based system that covered all short stays in hospitals in the state. Occupations were grouped into 12 major categories and conditions were coded using the International Classification of Diseases. Armed services personnel had the highest overall rate of hospital admissions, followed by transport and communications workers and by administrative and managerial workers. Injuries were the most common cause of referral to hospital. Four occupational groups, farmers and allied workers, miners and quarrymen, transport and communications workers, and craftsmen, production workers, and labourers were often associated with injury. Diseases of the musculoskeletal system and connective tissue were the second most common cause for referral and were increased in transport and communications workers, and in craftsmen, production workers, and labourers. Several other associations between causes of hospital admission and major occupational groups were observed, including associations of circulatory system diseases with professional and technical work and with administrative and managerial work. The excess of hospital admissions due to factors associated with occupation was estimated to be 12,665 admissions a year or 24.9% of the total in working men.

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

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.

Specifying morphological factors affecting rates of death due to malignant neoplasms.

This paper reports research which examines the relations between select social morphological factors of population size and density and rates of death due to malignant neoplasms among males and females within countries in the north-east and west regions of the U.S.A. between 1960 and 1970. Generally it was found that populations having a stable morphological structure have a negative relation with rates of death due to malignant neoplasms; populations experiencing a change in population morphology, particularly an increase in the number of persons per housing unit, have a positive relation with rates of death due to malignant neoplasms. The importance of tapping different dimensions of the spatial environment is illustrated as future research on the social epidemiology of malignant neoplasms is suggested.