Secular changes in early neonatal mortality in Norway, 1967-1981

[Neonatal mortality trends in São Luís, Maranhão, Brazil, from 1979 to 1996]

This study examined neonatal mortality trends in São Luís in the last 18 years. The early and late components were assessed and causes were classified according to SEADE Foundation criteria based on reducibility of deaths and timing of prevention (during prenatal care, childbirth, or neonatal care). Data were derived from official live birth and death records. We detected an unexpected increase in the neonatal mortality rate, due primarily to a steep rise in early neonatal deaths. Causes reducible by early diagnosis and treatment (other specific infections and other neonatal respiratory causes) and those partially reducible by adequate monitoring of pregnancy (preterm births, low birth weight, and respiratory distress syndrome) showed the largest increase. Conversely, the post-neonatal mortality rate fell. The infant mortality rate remained the same, reflecting these antagonistic trends. The important rise in the neonatal mortality rate from 1995 onwards suggests a deterioration in the quality of obstetric and neonatal services. The high cesarean rate and overcrowded neonatal services (i.e., unable to cope with increasing demands foe specialized neonatal care) indicate the urgent need for restructuring the mother and child health care system.

[The use of the "linkage" technique of information systems in cohort studies on neonatal mortality]

The utilization of record linkage of the mortality and birth information systems in studies of neonatal mortality is presented. The record linkage was used to obtain a cohort of live births and neonatal deaths in Santo André county, located within greater S. Paulo, in 1992. The procedures applied in order to avoid selection and effect biases, are discussed. The use of linked data allows the probabilities of neonatal deaths according to the exposure status of the variables which are registered on the birth certificate, and the identification of the live born at risk, to be calculated. Another advantage of the record linkage is the low financial cost of this type of study, because it uses information already registered.

Secular trends in the effect of socio-economic factors on birth weight and infant survival in Sweden

Time trends in the effect of socio-economic factors on low birth weight, stillbirth, perinatal deaths and deaths up to the age of one were studied using a medical birth registry linked to census information from 1975, 1980, and 1985. For each census year, delivery outcome the following year was studied. Two socio-economically different groups of women were studied, defined by occupation/education, cohabitation, and citizenship--one privileged and one under-privileged group. A difference in birth weight distribution was found between the two groups which is only partly explainable by different smoking habits in early pregnancy and did not substantially change during the ten year observation period. In 1976, there was virtually no difference in infant mortality between the two groups. In 1981 and 1986, infant mortality had decreased in both groups but more strongly so in the privileged group, and a difference between the groups therefore appeared.

Infant, neonatal, postneonatal and perinatal mortality in Spain, 1975-1984. Interregional and interannual differences

The national infant, neonatal, postneonatal and perinatal mortality in Spain does not reflect the differences which exist among regions. The aim of the present study is to demonstrate and to quantify these differences, as well as their annual trends. We have also attempted to define groups of regions presenting similar rates. The results of the study confirmed a decrease in all mortality rates during the analyzed period. Regions were grouped according to their rates. Differences between the top and the bottom groups (with the lowest and the highest rates, respectively) resulted in statistical significance. However, the differences between these and the middle groups were not sharply defined. In addition, a clear geographic aggregation was evidenced in both top and bottom groups. These differences are mainly due to economic and sanitary factors.