Paridade e tipo de parto influenciam a duração do aleitamento materno? Evidências do Estudo Pró-Saúde

Abstract

Breast milk is a crucial nutritional source that reduces mortality in early childhood and also brings benefits to maternal health. On the other hand, the causes of breastfeeding failure and early cessation lack investigation that could identify their factors and support more effective public policies. This study aims to analyze the relationship between the mode of delivery, parity, and breastfeeding duration, and to explore the existence of modifications in these associations according to educational level and dimensions of perceived social support. Breastfeeding duration was measured in months during which children were breastfed, using Kaplan-Meier survival curves. The chi-square test assessed differences between parity groups, while the Kruskal test and analysis of variance examined differences in breastfeeding duration. Cox proportional hazards models were used to estimate hazard ratios and their 95% confidence intervals, after adjusting for confounding variables. Of the 1,138 women included in the study, 8% reported never having breastfed, and among those who did, 26% breastfed until the 3rd month of the baby’s life, 28% until the 6th month, and 46% for a longer period. The "type of delivery" variable did not allow for the rejection of the hypothesis of no association through survival analysis. In the Cox models, the variable decade of birth emerged as a significant factor, with variable effects over time. Positive social interactions and material support were also associated with a lower risk of breastfeeding cessation. However, educational level did not significantly influence breastfeeding duration in this study. As for parity, the study showed that multiparous women are more likely to breastfeed than primiparous women. The survival analysis showed that the more children women have, the higher the likelihood of breastfeeding. In the adjusted analysis, from the first to the second child, the chance of weaning decreases by 2%; for the third child, the observed reduction was 10%; and for the fourth child, it is 29% lower, when compared up to 24 months. No dimension of social support or education confirmed the hypothesis of effect modification. Understanding and increasing awareness of the impacts associated with early weaning can contribute to increasing breastfeeding rates, aiming for better population health outcomes.