Effects of Enteral Feeding Regimens on NEC, Mortality, and Neurodevelopment in Very Preterm Infants

The goal of this clinical trial is to evaluate whether supplementing with pasteurized donor human milk (pHDM) or preterm formula (PTF) when own mother's milk (OMM) is insufficient can improve outcomes in very preterm infants born before 29 weeks of gestation. It also aims to assess whether routine use of human milk fortifiers benefits this population. The main questions it aims to answer are: Does supplementing OMM with pHDM or PTF improve survival without surgery-requiring necrotizing enterocolitis (NEC) by 34 weeks corrected gestational age? Is routine fortification of human milk better than selective fortification based on growth faltering? Researchers will compare: pHDM vs. PTF to see which better supports survival without severe NEC. Routine fortification vs. selective fortification to assess the impact on growth and long-term neurodevelopment. Participants will: Be randomized twice: * First, within the first week of life to receive either pHDM or PTF when OMM is insufficient * Second, in the second week of life to receive either routine fortification or selective fortification only if growth faltering occurs Receive feeding and care as per standard clinical practice Complete neurodevelopmental assessment at 2 years corrected age using the Griffiths Mental Development Scales. This multicenter, double-randomized, open-label randomized controlled trial is embedded in routine neonatal care and uses real-world data to assess both short- and long-term outcomes. COLLABORATE-China is being run in partnership with the UK-wide COLLABORATE trial sponsored by Imperial College London.

Inclusion Criteria: * Gestational age at birth less than 29 weeks; * No contraindications to enteral feeding; * Mother is willing to breastfeed. Exclusion Criteria: * For Randomization Group 1: If the infant has already received pasteurized human donor milk (pHDM), preterm formula (PTF), or nutritional fortifiers; * For Randomization Group 2: If the infant is exclusively fed with preterm formula and the mother has no intention to express breast milk;