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.

Study Overview

• Status: Completed
• Conditions: Comparative Nutrient Composition of Preterm and Term Human Milk
• Intervention / Treatment: Other: observational study

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 103

Contacts and Locations

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China
      • Sun Yat-sen University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Probability Sample

Study Population

Among these studies, most of them were performed in Europe. The sample size ranged from 10 to 2,633, with a median sample size of 49. All studies provided comparative data from mothers who delivered preterm and term infants, with gestational age consistently categorized as preterm (<37 weeks) and term (≥37 weeks). The stage of lactation at sample collection (including colostrum, transitional, and mature milk) was reported in most studies.

Description

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.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
lactating mothers or mothers providing human milk	Other: observational study; This study is a systematic review and meta-analysis. No intervention is administered to participants. Data regarding human milk composition are extracted and synthesized from previously published observational studies.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Energy content in human milk	The energy content in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Protein in human milk	The concentration of protein in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Fat in human milk	The concentration of fat in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Lactose in human milk	The concentration of lactose in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Concentration of IgA in human milk	The concentration of IgA in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Total nitrogen in human milk	The concentration of total nitrogen in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Lysozyme in human milk	The concentration of lysozyme in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Lactoferrin in human milk	The concentration of lactoferrin in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Lactalbumin in human milk	The concentration of lactalbumin in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Albumin in human milk	The concentration of albumin in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Sodium in human milk	The concentration of sodium in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Potassium in human milk	The concentration of potassium in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Calcium in human milk	The concentration of calcium in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Magnesium in human milk	The concentration of magnesium in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Phosphorus in human milk	The concentration of phosphorus in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Zinc in human milk	The concentration of zinc in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Copper in human milk	The concentration of copper in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Iron in human milk	The concentration of iron in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Iodine in human milk	The concentration of iodine in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Selenium in human milk	The concentration of selenium in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Manganese in human milk	The concentration of manganese in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Molybdenum in human milk	The concentration of molybdenum in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Vitamin E in human milk	The concentration of vitamin E in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Vitamin A in human milk	The concentration of vitamin A in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.
Concentration of Vitamin B6 in human milk	The concentration of vitamin B6 in human milk. Data will be extracted from included observational studies and expressed as mean ± standard deviation for comparison between preterm and term groups.	Human milk samples are collected during the defined lactation periods. Specifically, colostrum is defined as samples collected within 3-5 days postpartum, transitional milk within 7-14 days postpartum, and mature milk at ≥15 days postpartum.

Collaborators and Investigators

• Sponsor: Sun Yat-sen University

Study record dates

Study Major Dates

• Study Start (Actual): July 6, 2022
• Primary Completion (Actual): July 8, 2024
• Study Completion (Actual): September 12, 2025

Study Registration Dates

• First Submitted: February 3, 2026
• First Submitted That Met QC Criteria: February 3, 2026
• First Posted (Actual): February 10, 2026

Study Record Updates

• Last Update Posted (Actual): April 15, 2026
• Last Update Submitted That Met QC Criteria: April 11, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Investigative Techniques; Methods; Observation
• Other Study ID Numbers: HMP

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No