Formula supplementation in hospital and subsequent feeding at discharge among women who intended to exclusively breastfeed: An administrative data retrospective cohort study

Background: Among women who intend to exclusively breastfeed, it is important to identify mothers and their infants who have a greater risk of formula supplementation in hospital, and are unlikely to recover exclusive breastfeeding at discharge. We investigated factors associated with in-hospital formula feeding among healthy term infants born to women who intended to exclusively breastfeed, and among this group, predictors of infant feeding at discharge. Methods: Retrospective cohort study utilizing routinely collected clinical data for women who intended to exclusively breastfeed and gave birth to healthy term infants in five hospitals in New South Wales, Australia, 2010-2013. Robust Poisson regression was used to obtain adjusted relative risks (aRR) for the associations between formula feeding in hospital, feeding at discharge, and associated factors. Results: Of 24 713 mother-infant dyads in the study population, 16.5% received formula in hospital. After adjustment, the strongest predictors of formula supplementation were breastfeeding difficulties (aRR 2.90 [95% confidence interval {CI} 2.74-3.07]), Asian born mother (aRR 2.07 [95% CI 1.92-2.23]), and neonatal conditions (aRR 2.00 [95% CI 1.89-2.13]). Among infants who received formula (n=3998), 49.3% were fully breastfeeding at discharge, 33.1% partially breastfeeding, and 17.5% formula-only feeding. Compared with formula-only feeding, special care nursery admission (aRR 1.23 [95% CI 1.17-1.30]) and >= 1 neonatal conditions (compared with none) were most strongly associated with fully breastfeeding at discharge (aRR 1.21 [95% CI 1.16-2.16]). Conclusion: Women and their infants who receive formula in hospital need additional support to attain exclusive breastfeeding by hospital discharge. Such support is especially needed for younger women, smokers, and women with breastfeeding difficulties.