PC2026: Formula Supplementation on First Day of Life in Breastfed Infants: How Much Is Too Much?

Background: AAP recommends exclusive breastfeeding, beginning within an hour of birth. Although mothers are encouraged to allow infants breastfeed on demand based on their nutritional needs, caregivers and healthcare providers may feel the need to supplement breastfeeding with formula due to various reasons including but not limited to, perceived concerns of insufficient milk production or suboptimal infant intake. Because there are limited guidelines on formula feeding amount and interval rates on the first day of life, there is a risk of excessive supplementation which could cause feeding intolerance (FI) and may subsequently lead to decrease in formula volume or even switching of formulas. The aim of this study was to explore factors associated with supplementation and to correlate the feeding profile, including volume of supplementation, and the incidence of FI in breastfed newborns supplemented with formula within the first 24 hours of life (24 HOL).

Methods: We conducted a single center, retrospective chart review of infants from March 2018 to March 2021, born at gestational age (GA) ≥35 weeks and admitted to the newborn nursery after birth. Maternal and infant demographic variables, as well as feeding data in the first 24 HOL were assessed. Cases in our study were defined as infants with FI evidenced by chart documentation of emesis, abdominal distension, and/or switching to a sensitive formula within the first 24 HOL. The relationship between FI, initial feeding characteristics, and other epidemiological variables were investigated using univariate and multivariate analyses.

Results: Of the total 6650 infants, 21.9% (n=1456) were exclusively breastfed (Group B) and 46.6% (n=3102) received supplementation in addition to breastfeeding (Group S). Neonatal factors (birth weight and GA) as well as maternal demographics, type of insurance, mode of delivery, anesthesia during delivery, and history of diabetes, hypertension and psychiatric illness were analyzed in relation to formula supplementation (Table 1). The incidence of FI was higher in Group S (20.4% vs 3.0%; p< 0.0001) and associated with a higher median volume intake in ml/kg (12.4 vs 10.6; p< 0.0001). After adjusting for confounding variables, there was an incremental increase in the odds of FI with formula volume of, 5-10ml/kg (odds ratio [OR] = 2.8, 95% confidence interval [CI] 1.9-4.3), 10-15ml/kg (OR = 4.7, 95% CI 3.1-6.8), and >15ml/kg (OR = 5.2, 95% CI 3.4-7.9) (Table 2).

Conclusion: Identifying factors related to formula supplementation may help to better allocate resources to increase early breastfeeding rates. In infants who receive supplementation in the first 24 HOL, higher volumes are associated with feeding intolerance. Guidelines stipulating the safe amount of supplementation would be beneficial in the newborn nursery.