Birth weight and maternal characteristics at the Maternity of Campinas along 25 years

Abstract

OBJECTIVE: To study the secular trends of birthweight and maternal characteristics at the Maternity of Campinas, São Paulo, Brazil, from 1971 to 1995. METHODS: The authors studied 18,262 newborns in the Maternity of Campinas. Birthweight and maternal characteristics were analyzed comparing changes occurred every 5 years. The data were analyzed by chi-square test, analysis of variance, multivariate logistic regression, and population attributable risk. RESULTS: The results showed a positive trend for birthweight only in the period between 1976 and 1980 (P<0.05). The frequency of low birthweight was constant, remaining around 8.0%, but towards the end of the studied period, it started to be predominantly seen among preterm newborns. The frequency of favorable weight was below 70.0%. The authors observed an increase in the number of pregnant adolescents, pregnant women working outside home, unmarried mothers, cesarean sections, frequency of preterms, and decrease of parity (P<0.05). The maternal characteristics associated with low birthweight were: unmarried status, maternal age of 17 years old or less, maternal age of 35 years or more, public medical-hospital assistance, nonwhite skin color, primiparity, multiparity, and female newborns. In the 90s, 44.3% of low birthweight was attributed to preterm newborns. CONCLUSIONS: Even with a positive development of the general conditions considered important to improve population s health, birthweight has not increased, probably as a reflex of other changes that held back this advance.