# The Impact of Donating Human Milk on the Health of the Donor and Their Infant: Evidence from Two Systematic Reviews

## TL;DR

This study finds no clear evidence that donating human milk harms or benefits donors or their infants in the short term.

## Contribution

The study provides the first systematic evaluation of the health effects of human milk donation on both donors and their infants.

## Key findings

- No significant differences were found in health outcomes for donors, including postpartum depression, mastitis, or breast engorgement.
- Donor infants showed no differences in feeding intolerance, weight gain, or need for phototherapy compared to non-donor infants.
- The certainty of evidence for all outcomes was rated as very low.

## Abstract

Using human milk has been associated with decreased morbidity and mortality in preterm/low birth weight infants. Donor human milk is recommended when maternal milk is unavailable. The benefits of donor human milk for the recipient are well documented, but the impact of donation on donors and their infants is not clear. We aimed to evaluate the effects of donation human milk on donors and their infants. Literature searches were conducted (April 2024) to identify studies (observational, quasi-experimental, and randomized control trials) assessing the impact of human milk donation on donor health, nutrition, well-being, and lactation and on their infants’ health, growth, and development. Bias was assessed using the Risk of Bias in Non-randomized Studies – of Interventions scale. Meta-analysis was conducted when possible. Certainty of evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach. Nine studies examined donor outcomes, and 6 studies examined donor infant outcomes. No differences were found between donors and nondonors regarding the prevalence of overweight [risk ratio (RR): 1.27; 95% confidence interval (CI): 0.81, 2.01], postpartum depression (RR: 0.60; 95% CI: 0.21, 1.72), postpartum anxiety (RR: 0.84; 95% CI: 0.59, 1.18), need to pump for their infant (RR: 1.09; 95% CI: 0.63, 1.89), mastitis (RR: 1.48; 95% CI: 0.71, 3.05), chapped/cracked nipples (RR: 0.61; 95% CI: 0.34, 1.12), and breast engorgement (RR: 1.88; 95% CI: 0.94, 3.77). Similarly, no differences were found between donor and nondonor infants regarding feeding intolerance (vomiting) (RR: 1.26; 95% CI: 0.53, 3.01), slow weight gain (RR: 0.36; 95% CI: 0.13, 1.02), oral thrush (RR: 0.55; 95% CI: 0.12, 2.37), or need for phototherapy (RR: 2.21; 95% CI: 0.93, 5.23). The certainty of evidence was very low for all outcomes. Limited, very low certainty evidence does not support any short-term harms or benefits of human milk donation for donors or their infants. The protocols for both studies were registered with the International Prospective Register of Systematic Reviews (PROSPERO) on March 26, 2024. Study IDs: CRD42024529222 and CRD42024528803.