Impact of Colostrum Oropharyngeal Immunotherapy on Postnatal Growth in Preterm Infants

The treatment group will undergo the following treatment protocol within the initial 48-72 h: Investigators will select storage bags with the closest lactation time to the current time while wearing sterile gloves for the entire procedure. Next, using two 1-mL sterile syringes, investigators will draw 0.1 mL of colostrum from each bag and tightly cap the needle hubs to ensure hygiene and safety. Each syringe will be labeled with the hospitalization number, the infant's name, and the date of the mother's colostrum expression. The bags will be then left to sit at room temperature for 5 min to reach an appropriate temperature for oropharyngeal administration of the colostrum. Subsequently, the tip and cap of the first syringe will be removed, and the colostrum will be slowly injected along the right oral mucosa of the participants, lasting at least 20 s. After injection, a sterile cotton swab will be used to gently wipe the right buccal mucosa for at least 10 s.

For the control group, normal saline will be used instead of colostrum. The rest of the procedure will be the same as that for the treatment group.