# Caesarean Delivery Influences Breast Milk Composition—A Narrative Review

## TL;DR

This review explores how caesarean delivery affects breast milk composition and its potential impact on infant health.

## Contribution

The paper provides a comprehensive review of how caesarean delivery transiently alters breast milk composition, particularly in early lactation stages.

## Key findings

- CS is associated with changes in colostrum and transitional milk, including macronutrients, immune molecules, and microbiota.
- Alterations in breast milk composition may have both beneficial and detrimental effects on neonatal health.
- Findings for mature milk are inconsistent and often confounded by other factors.

## Abstract

Delivery by caesarean section (CS) is increasingly common worldwide and has been associated with altered health outcomes in offspring, which can be partially mitigated with breastfeeding. Interestingly, the mode of delivery itself may influence the composition of human milk. The aim of this narrative review was to comprehensively examine current evidence on the impact of CS on breast milk composition and to discuss its potential implications for neonatal and infant health. A literature search of the MEDLINE database was conducted in July 2025. It identified 1212 studies addressing associations between mode of delivery and human milk components, of which 54 were included in the qualitative synthesis. Available evidence suggests that CS is associated with transient, lactation stage-dependent alterations in breast milk composition, most pronounced in colostrum and transitional milk. Reported changes include differences in macronutrients, mineral content, immune-related molecules, hormones, antioxidants, microbiota, microRNA profiles, and other bioactive components. Findings related to mature milk are less consistent and often influenced by confounding factors. While some CS-associated alterations may slightly reduce the beneficial effect of breastfeeding, e.g., reducing certain antimicrobial or nutritional components, other changes seem to be potentially advantageous for the neonate/infant after CS, in particular in immune-related factors. Overall, the clinical significance of these compositional differences remains unclear, as no studies have directly linked CS-related changes in milk composition to long-term infant outcomes. Further well-designed longitudinal studies are needed to clarify these associations. Regardless of delivery mode, breastfeeding remains the optimal feeding strategy and a key intervention to support infant health after CS.