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Updated: Jan 16, 2026
Individualized Reconstitution of Human Milk Microbiota: A Feasible Approach in Real-World Settings
Published on: February 7, 2025
Comparing Impacts of Donor Human Milk to Formula Supplementation on the Gut Microbiome of Full-Term Infants Born Via
Meredith Merilee Brockway1,2,3, Maria Khalid1, Yasmeen Khalil1
1Faculty of Nursing, University of Calgary, Calgary, AB, Canada.
Insights
Donor human milk supplementation may offer benefits for infant gut microbiome development and maternal mental health compared to formula, particularly for infants born via Cesarean section. This pilot study informs larger trials on infant health outcomes and breastfeeding.
Area of Science:
- Investigates the impact of infant nutrition on gut microbiome development and overall child health.
- Focuses on maternal and infant health outcomes in the context of early-life feeding practices.
Background:
- Disrupted infant gut microbiome in the first 1000 days can cause long-term health issues.
- Cesarean delivery and formula feeding negatively affect infant microbiome and maternal mental health.
- Donor human milk is a potential alternative to formula for supplementation.
Purpose of the Study:
- To compare donor human milk versus formula supplementation in full-term infants born via Cesarean section.
- To assess the impact on infant gut microbiome, infant health, breastfeeding, and maternal mental health.
Main Methods:
- Pilot randomized controlled trial involving 187 full-term infants born via Cesarean section requiring supplementation.
- Comparison of donor human milk versus formula supplementation in the first postnatal week.
- Data collection on infant stool samples, breastfeeding, maternal mental health, and child health at multiple postpartum time points (1 week to 36 months).
Main Results:
- Study will generate data on the association between supplementation type and infant microbiome composition.
- Will provide insights into breastfeeding exclusivity, duration, and infant health outcomes.
- Preliminary data on maternal mental health and longer-term child health outcomes will be collected.
Conclusions:
- The findings will inform a larger longitudinal mixed-methods randomized controlled trial.
- Evidence may guide policies to increase accessibility and awareness of donor human milk.
- Highlights the potential of donor human milk as a beneficial supplementation option.
Background:
A disrupted gut microbiome during an infant's first 1000 days of life can lead to long-lasting negative effects on child health. Cesarean delivery and formula feeding are two factors that can detrimentally impact infant microbiome development as well as maternal mental health. Donor human milk may be a superior supplementation alternative to formula.
Research Aim:
To examine donor human milk supplementation compared to formula supplementation in full-term infants born via Cesarean section and the impact on the infant gut microbiome, infant health outcomes, breastfeeding outcomes, and maternal mental health.Methods and Planned Analyses:We are conducting a pilot clinical randomized controlled trial, comparing donor human milk to formula supplementation for 187 full-term infants born via Cesarean section who are breastfeeding and require supplementation in the first postnatal week of life. Infant stool samples, breastfeeding outcomes, maternal mental health, and child health outcomes will be measured at 1-week, 3-, 6-, and 12-months postpartum. Additionally, child health and maternal mental health are being assessed at 18- and 36-months postpartum.
Discussion:
This study will generate essential data on the association between supplementation types and the full-term infant microbiome, breastfeeding exclusivity and duration, and infant health. It will also provide preliminary data to inform a multi-site, longitudinal mixed-methods randomized controlled trial that will assess longer term child health outcomes. This evidence may be used to inform guidelines and policies that will increase accessibility to and raise awareness of donor human milk as a supplementation option in this population.
