Infant feeding practices among macrosomic infants: A prospective cohort study

The health benefits of breastfeeding are well recognised, but breastfeeding rates worldwide remain suboptimal. Breastfeeding outcomes have yet to be explored among women who give birth to macrosomic (birthweight ≥4000 g) infants, a cohort for whom the benefits of breastfeeding may be particularly valuable, offering protection against later-life morbidity associated with macrosomia. This longitudinal prospective cohort study aimed to identify whether women who give birth to macrosomic infants are at greater risk of breastfeeding non-initiation or exclusive breastfeeding (EBF) cessation. A total of 328 women in their third trimester were recruited from hospital and community settings and followed to 4 months post-partum. Women gave birth to 104 macrosomic and 224 non-macrosomic (<4000 g) infants between 2018 and 2020. Longitudinal logistic regression models calculated odds ratios (ORs) and 95% confidence intervals (CIs) to assess likelihood of EBF at four timepoints post-partum (birth, 2 weeks, 8 weeks, and 4 months) between women who gave birth to macrosomic and non-macrosomic infants, adjusted for maternal risk (obesity and/or diabetes), ethnicity and mode of birth. Macrosomic infants were more likely to be exclusively breastfed at birth and 2 weeks post-partum than non-macrosomic infants with adjusted OR = 1.94 (95% CI: 0.90, 4.18; p = 0.089) and 2.13 (95% CI: 1.11, 4.06; p = 0.022), respectively. There were no statistically significant associations between macrosomia and EBF at 8 weeks or 4 months post-partum. Macrosomia may act as a protective factor against early formula-milk supplementation, increasing the likelihood of EBF in the early post-partum period, but rates of exclusive breastfeeding continued to decline over the first 4 months post-partum.