Breastfeeding Ambulatory Supplementation With Preterm Formula Versus Fortifiers Achieves Similar Growth at 40 Weeks: A Pilot Study in Preterm Infants

Aim: This study evaluates whether liquid formula supplementation for preterm infants was non-inferior to breast milk fortifiers regarding growth and adherence to exclusive breastfeeding in an outpatient Kangaroo Mother Care Program from Colombia. Methods: An open-label randomised trial was initiated in 2016 and interrupted in 2018 because of the lack of fortifiers in the country and included 81 preterm infants born between 32 + 0 and 36 + 6 weeks/days of gestational age. Infants were assigned to receive either breast milk fortifiers or liquid formula, with outcomes assessed up to 40 weeks. Results: No significant differences in anthropometric measurements were observed between the groups. More than two-thirds (69%) achieved exclusive breastfeeding, with higher rates in the fortifier group (73.0% vs. 53.0%, p = 0.06). This tendency persisted up to 6 months of corrected age. Breastfeeding was discontinued more frequently in the liquid formula group despite showing better gastrointestinal tolerance, ease of administration, and lower cost and contamination for home use. Conclusions: Liquid formula supplementation showed growth outcomes comparable to those of breast milk fortifiers at 40 weeks. Further research with larger samples is recommended to validate outcomes.