Research has shown that provision of mother's milk is the optimal way to feed very low birthweight (VLBW) infants. Many infants will require a supplement to mother's milk, pasteurized donor human milk (PDHM) compared to preterm formula is the most appropriate supplement as it has been shown to reduce the risk of necrotizing enterocolitis (NEC).

Most available evidence suggests neither mother's milk nor PDHM will meet the elevated nutritional requirements of VLBW infants without multi-nutrient fortification. Globally, the current standard of care is to use bovine protein-based nutrient fortifiers to meet these elevated nutrient requirements. Given the known benefits of mother's milk, the reduction in the risk of NEC with use of PDHM as a supplement, and the availability of human milk-based multi-nutrient fortifiers (HMBF), there has been considerable interest in the efficacy of HMBF over the less costly bovine milk-based fortifiers (BMBF).

This study is an analysis of individual participant data merged from randomized control trials that examined the efficacy of HMBF compared to BMBF during hospitalization, on the risk of death and severe morbidity or major feeding interruption. Participants of the trials included in the analyses were fed exclusively with human milk or a supplement of pasteurized donor human milk (PDHM).

Only two RCTs met this criteria -OptiMoM and the N-forte trial. In both studies the intervention aligned to commence upon randomization into the HMBF or BMBF groups. The difference between the OptiMoM and N-forte feeding protocols was that the later allowed for individualized fortification based on milk analysis whereas OptiMoM used standard fortification, predominant in Canada and globally.

For OptiMoM, the feeding intervention continued until infants were 84 days of age, discharge, or when the infant consumed ≥2 complete oral feeds daily. For N-forte trial, the feeding intervention ended when babies reached 34 weeks (zero days). Both studies followed participants and continued data collection if transferred to a level II NICU for convalescence (OptiMoM) or home care service followed closely by NICU nurses (N-forte) until discharge.

Inclusion Criteria:

• Infant is a participant of the OptiMoM or the N-Forte trial.

Participants of the OptiMoM and N-Forte trial are VLBW infants fed exclusively Human Milk.

Data transfer will take place via Secure File Transfer Protocol (SFTP). A sub-agreement which covers data sharing and confidentiality is in place.

February 2025 to February 2027

The Hospital for Sick Children (Lead Dr. Deborah L. O'Connor PhD, RD): Data analysis.

Umeå University - (Lead Dr. Magnus Domellöf MD, PhD): Data analysis.