Inclusion and exclusion criteria
| Inclusion | Exclusion | |
| Article type | Published peer-reviewed research articles | Review articles, preprint articles, conference abstracts, grey literature |
| Language | English, Spanish and French | All languages other than English, Spanish and French |
| Country | All countries | None |
| Publication date | From inception until 31 January 2024 | Studies published after 31 January 2024 |
| Model of research | Human | Other than human |
| Cell population of characterisation/evaluation | Leucocytes, including, but not restricted to:
| Any other cell type present in breast milk including haematopoietic stem cells |
| Milk sampling | Any type of human milk (colostrum, transitional milk or mature milk) at any time of sampling (prefeeding and postfeeding, mornings/evenings, etc). | No restriction |
| Demographic and clinical data of the cohort participants | Human mothers, mothers of all ages, nationalities and health stages. All types of delivery. Any neonate sex. Any neonatal term (preterm, full term, post-term. Any maternal or infant condition.) | No restriction |
| Extras | Maternal pathologies or special medical conditions | No restriction |