Breastfeeding duration and exclusivity among early-term and full-term infants : a cohort study

Abstract

Background: As compared to full-term infants (39–41 weeks of gestation), early-term infants (37–38 wk) are at increased risk of adverse outcomes, including shorter exclusive breastfeeding (EB) duration and continued breastfeeding. Objectives: To compare early-term with full- and late-term infants regarding the prevalence of EB at 3 mo and any breastfeeding at 12 mo. Methods: Data sets from two population-based birth cohorts conducted in the city of Pelotas, Brazil, were combined. Only term infants (37 0/7 through 41 6/7 weeks of gestation) were included in the analyses. Early-term infants (37 0/7 through 38 6/7 wk) were compared to the remaining term infants (39 0/7 through 41 6/7 wk). Information on breastfeeding was gathered through maternal interviews at the 3-mo and 12-mo follow-ups. The prevalence of EB at 3 mo and any breastfeeding at 12 mo with 95% CIs were calculated. Crude and adjusted prevalence ratios (PRs) were obtained through Poisson regression. Results: A total of 6395 infants with information on gestational age and EB at 3 mo and 6401 infants with information on gestational age and any breastfeeding at 12 mo were analyzed. There was no difference between early-term infants and the remaining term infants regarding the prevalence of EB at 3 mo (29.2% and 27.9%, respectively) (P ¼ 0.248). Prevalence of any breastfeeding at 12 mo was lower in early-term infants than among those born between 39 0/7 and 41 6/7 weeks of gestation (38.2% compared with 42.4%) (P ¼ 0.001). In the adjusted analysis, the PR for any breastfeeding at 12 mo was 15% lower in the early-term group than in the remaining term infants (PR ¼ 0.85; 95% CI: 0.76–0.95) (P ¼ 0.004). Conclusions: The prevalence of EB at 3 mo was similar among term infants. Nonetheless, in comparison with the remaining infants born at term, early-term infants were at increased risk of having been weaned before reaching 12 mo of age.