Bovine-based breast milk fortifier and neonatal outcomes in premature infants <32 weeks’ gestational age

Purpose: To examine if the use of bovine-based breast milk fortifier (BMF) in preterm infants plays a role in the development of necrotising enterocolitis (NEC), or an increase in all-cause mortality. Methods: : Retrospective audit of 952 preterm infants, born <32 weeks gestational age (GA) between January 2010 and September 2020 at a tertiary surgical level 3 Neonatal Intensive Care Unit (NICU) (St George’s Hospital, London, United Kingdom). Odds ratios (OR), risk ratios (RR), and number needed to treat (NNT) were calculated for the total cohort, and in subgroup analyses by GA. Results: : Use of BMF increased significantly across the ten-year study timeframe, from 10.5% of infants in 2010 to 45.8% in 2020. Conversely, NEC rates have been stable across this timeframe (6.3% from 2010 – 2014 and 5.8% from 2015 – 2019). BMF was not associated with an increased risk of developing NEC in preterm infants <32 weeks GA (RR 0.63), including within subgroup analyses. BMF was not associated with an increased risk of all-cause mortality within the cohort (RR 0.31). In the most clinically vulnerable subgroup, GA <26 weeks, BMF use was associated with a decreased risk of developing NEC (RR 0.36, P =0.019, NNT 4.80 – 30.3) and decreased all-cause mortality (RR 0.30, P =.0033, NNT 3.91 – 15.65). Conclusion: Use of bovine BMF was not associated with adverse outcomes in this study. BMF use was associated with a decreased rate of adverse outcomes in the most clinically vulnerable infants.