[Birth weight and hospital mortality among liveborn infants, 1975-1996]

To assess the trend of birth weight and hospital mortality rate of newborns, in a maternity hospital of Campinas, SP.

A total of 215,435 births of a maternity hospital in Campinas, S. Paulo State, Brazil, was studied between 1976 and 1996. Information was collected from registration files and annual reports of medical care. All the newborns from that period were included. The causes of death that occurred before the discharge, regardless the age, were analyzed. For data analysis, Epi info 6.01 method was used.

Birth weight distribution remained the same for the 22 years period studied. Low birth weight was seen in about 9% of newborns, and accounted for 82% of hospital deaths in 1996. Below average weight was observed in about 24% of the newborns. We could notice an improvement in survival for those who had a birth weight between 1,000 g and 1,999 g. In 1975, 13.3% of those with weights between 1,000 g and 1,499 g survived and 73.8% of those who weighed between 1,500 g and 1,999 g. In 1996, survival rates increased to 69. 1% and 87.7% respectively. Hospital mortality rate among infants whose weight was below 1,000 g remained high, between 78.9% and 100%, even in the 90's. There was a reduction of hospital mortality rates from 17 to 11 per thousand live births.

There was not any change in the distribution of birth weight despite improvements in life conditions of Campinas population. The decrease in mortality rates is due to improvement in health care which is very expensive. There is a need of other studies to allow why birth weight distribution remained the same.