Comparison of Nutrient Content Between Preterm and Term Human Milk: a Systematic Review and Meta-analysis

Comparison of Nutrient Content Between Preterm and Term Human Milk: a Systematic Review and Meta-analysis

The purpose of this study is to thoroughly evaluate nutrient disparities between preterm and term human milk.

Preterm birth (gestational age of less than 37 weeks) is a major global health issue, associated with a high burden of mortality and long-term morbidity. Achieving optimal nutrition is critical for improving outcomes in this vulnerable population. However, the specific nutritional requirements for supporting postnatal growth akin to intrauterine rates are exceptionally high. While human milk is the recommended foundation of nutrition, its unfortified use may not meet these demands, and common alternatives like preterm formula present a balance of potential benefits and risks. Crucially, formulating effective nutritional strategies hinges on a precise understanding of the composition of preterm human milk itself. Existing evidence on this composition, especially regarding micronutrients and their influencing factors, is inconsistent and incomplete. Prior reviews have largely focused on macronutrients, leaving a gap in the synthesized evidence regarding micronutrient levels and their key determinants. Therefore, we performed this systematic review and meta-analysis to quantitatively compare the nutrient profile of preterm and term human milk and to evaluate the influence of factors such as lactation stage on these differences.

Inclusion Criteria:

• Studies needed to be population-based observational designs and report nutrient composition data for both preterm and term human milk. They must clearly define gestational age (preterm: 25-36 weeks; term: 37-42 weeks) and examine at least one comparable nutrient in both groups, such as energy, macronutrients (such as protein, fat, lactose), and/or micronutrients (including minerals like calcium and phosphorus, and vitamins such as vitamin D). We included articles published in Chinese or English only.

Exclusion Criteria:

• Studies were excluded if they focused solely on mothers with specific medical conditions (such as malnutrition, mastitis, or diabetes), if they involved nutrient supplementation as an intervention, or if they were published in languages other than Chinese or English.