Table 1.

Inclusion and exclusion criteria for preterm infants receiving different types of nutrition and whose microbiota was studied.

Inclusion criteria	Exclusion criteria
BW ≤ 1.500 g and/or GA ≤ 32 weeks	GA > 32 weeks
Enteral intake (≥ 150 mL/kg/day)	Parents refuse to participate/sign informed consent
The principal nutrient received (MOM, DHM, or formula) represents 80% of the intake	Mixed breastfeeding
DHM from just one donor to one premature or maximum of two different donors	Chromosomopathies
No additional treatments that could alter the microbiota (e.g., probiotics) or oxidative status (e.g., vitamins C, A, and E)	Major malformations or surgery of the digestive tract

GA, gestational age; BW, birth weight; MOM, mother’s own milk; DHM, donor human milk.