Background Human breast milk-fed preterm infants can accumulate nutrient deficits leading to extrauterine growth restriction. Feeding preterm infants with multi-nutrient fortified human milk could increase nutrient accretion and growth rates and improve neurodevelopmental outcomes. Concern exists, however, that multi-nutrient fortifiers are associated with adverse events such as feed intolerance and necrotising enterocolitis. Objectives To determine whether multi-nutrient fortified human milk, compared with unfortified human milk, a ects important outcomes (including growth rate and neurodevelopment) of preterm infants without increasing the risk of adverse e ects (such as feed intolerance and necrotising enterocolitis).