Maternal nutrition and duration of breastfeeding in a birth cohort in Pelotas, Brazil

The effects of maternal nutritional status on the duration of breastfeeding are inconsistent in the literature. A population-based cohort study was set to investigate this relationship. Nine hundred and seventy seven mothers giving birth in 1993 (20% of that year's births) were studied. Studied maternal characteristics included nutritional status, social, economic, and demographic variables. The effects of these variables on the prevalence of breastfeeding at six months were analyzed through logistic regression. Cox regression was applied to analyze the effects on the duration of breastfeeding. Multivariate logistic regression analysis showed a higher prevalence of breastfeeding among women with a pre-pregnancy weight of 49 kg or more (odds ratio = 1.31; CI(95%) 1.04 - 1.64). The association with maternal height was not significant (p=0.06). Cox regression also showed a non-significant protective effect of having a higher pre-pregnancy weight (hazard ratio = 0.91; CI(95%) 0.82 - 1.01). The duration of breastfeeding duration was not associated with maternal height. Weight gain during pregnancy was not associated with breastfeeding in either analyses. Other variables associated with the duration of breastfeeding in both analyses were maternal age, parity, smoking, and gestational age. Family income was associated with the prevalence of breastfeeding at six months, and birthweight was associated with the duration of breastfeeding. Pre-pregnancy nutritional status is a stronger predictor of breastfeeding than weight gain during pregnancy.