Birthweight is the result of many factors (organic, psychological, social) acting on the genetic potential of the fetus. Consequently, its distribution is different according to the characteristics of the population. In this paper the authors studied the weight at birth of live newborns (from 1978 to 1979) in the two big maternity hospitals, in Florianópolis, responsible for 90% of all births in the area, by sex, litter size and mother's health security. The authors verified that the mean birthweight of the 18,491 live newborns was 3,347.6gr. In that population 5.3% of the newborns were low birthweight infants, and 11.1% weighed 4,000gr or more. Male newborns weighed significantly more than female babies, and the same difference occurred between single and multiple births. The relationship between the newborn's birthweight and the kind of health security the mother had showed that the mothers who didn't pay any kind of health security had babies with lower birthweight than those of the mothers who subscribed to some health security scheme. The data showed that this population has a low incidence of low birthweight babies, with a distribution similar to that observed in developed countries.
Birth weight; Infant, low birth weight; Sex factors; Socioeconomic factors
