Impact of in-hospital formula supplementation on breastfeeding outcomes in Hong Kong infants

The acceptance of free infant formula by hospitals has been recognized by the WHO as negatively impacting breastfeeding practices. In Hong Kong, although this practice is currently under review, all public hospitals continue to accept free infant formula from manufacturers. The aim of this study was to determine the impact of in-hospital infant formula supplementation on breastfeeding outcomes. A sample of 1283 breastfeeding mother-infant pairs was recruited from four public hospitals in Hong Kong and followed prospectively for 12 months or until weaned. A Cox Proportional Hazards Model was used to assess the impact of in-hospital supplementation on breastfeeding outcomes. The median duration of breastfeeding in the sample was 9 weeks. Only 26.9% of babies were exclusively breastfed during the first 24 hours of hospitalization and 11.2% received no breastmilk at all. Substantial variation was observed between hospital sites with rates of exclusive breastfeeding ranging from 16.1 to 33.6% and rates of no breastfeeding ranging from 5.7 to 16.4%. In-hospital formula supplementation significantly increased the risk of early weaning (HR=1.27; 95% CI=1.14, 1.42). In the multivariate model, factors positively associated with breastfeeding duration were exclusive breastfeeding in hospital (HR=.74; 95% CI=.60, .91), intended weeks of breastfeeding (HR=.96; 95% CI=.95, .97), and higher maternal education (HR=.70; 95% CI=.58, .86). In-hospital formula supplementation was common in this sample and significantly reduced the duration of breastfeeding. The cessation of free formula supplied to Hong Kong public hospitals could substantially reduce the frequency of supplementation and would also likely increase the duration of breastfeeding.