Effect of breastfeeding and morbidity on the development of low birthweight term babies in Brazil

Low birthweight (LBW) occurs in 17% of births in developing countries and m any of them are full term. The subsequent development of LBW term infants i s poorer than higher birthweight children and more likely to be affected by poor social circumstances. We investigated the effects of morbidity and br eastfeeding on the development of these LBW term infants. Two parallel coho rts (n = 131 + 131) of LBW term (1500-2499 g) and higher birthweight (3000- 3499 g) infants were recruited from six maternity centers in northeast Braz il. The longitudinal prevalence of morbidity and the frequency of breastfee ding over the first 6 mo of life were assessed. The infants' development wa s assessed on the Bayley Scales at 6 and 12 mo, and we previously reported that the low birthweight group had lower scores than the higher birthweight group. Hospitalizations in the first 6 mo were negatively associated with 6-mo and 12-mo Bayley scores in both groups. Among LBW infants, but not hig her birthweight infants, there were significant associations between the pr evalence of diarrhea and mental and motor development at 6 mo and mental de velopment at 12 mo. Breastfeeding frequency in the first 4 wk of life was p ositively associated with mental development in both birthweight groups at 6 mo but not at 12 mo. Breastfeeding beyond 4 wk was not associated with th e children's development. We conclude that low birthweight infants are espe cially vulnerable to the effects of diarrhea, and the greater frequency and differential effect of diarrhea partly explains their poorer development.