DOnor Milk to REpair the Full-term Infant MIcrobiome in Infants Born Via Cesarean Section.

The objective of this novel study is to establish proof of concept using a pilot randomized controlled trial to determine the effect of DHM compared to formula supplementation on the microbiome in full-term infants who are born via caesarean section and require supplementation. Secondarily, this study aims to compare the infant health outcomes of sleep and growth between groups to assess if these outcomes are mediated by infant feeding type or potential differences in microbial signatures. Finally, this study will compare maternal outcomes of depression, anger, breastfeeding self-efficacy and breastfeeding rates between groups.

The infant gut microbiome plays a critical role in the developing immune, neurologic, and endocrine systems. Yet, most infants experience early life disruptions (ELDs) to their microbiome that have potential long-term health and development impacts. A major source of disruption is caesarean section (c-section) delivery because the infant is born surgically and is not exposed to important commensal bacteria required to establish the infant microbiome. Currently in Canada, over 28% of infants are born via c-section.

Exclusive breastfeeding can improve gut microbiota composition in infants who are born via c-section. However, approximately 60% of infants born via c-section require formula supplementation in their first week of life. Evidence indicates that even one bottle of formula can further disrupt the gut microbiome.

Donor human milk (DHM) is a superior alternative to formula when supplementation is required as its biotic properties minimize perturbations to the infant gut microbiome and may help to repair the microbiome in infants who experience ELDs. Yet, while DHM is well researched in preterm populations, evidence on the impact of DHM as a therapeutic intervention on the full-term infant gut microbiome is lacking.

The hypothesis of this study is: that replacing formula with DHM supplementation will minimize gut microbiome dysbiosis and foster homeostasis following supplementation. In addition, it is hypothesized that improved homeostasis will promote improved sleep and growth outcomes in participant infants. Finally, mothers whose infants receive DHM will have lower depression and anger scores and higher breastfeeding self-efficacy and exclusive breastfeeding rates compared to mothers whose infants receive formula.