Impact of delivery mode on the levels of essential trace elements in breast milk

Aim: This study investigated whether the parturition mode (vaginal or cesarean [C-] section) affects breast milk concentrations of four essential trace elements (iron, copper, zinc, and manganese). Methods: Women giving birth at seven hospitals in seven different regions of China were enrolled in the study. Each participant provided breast milk, collected on postpartum day 3–5, for determination of iron, copper, zinc, and manganese concentrations. Breast milk concentrations of the subject trace elements were compared between women giving birth vaginally or via C-section. Results: Of the 1243 women enrolled in the study, 617 (49.6%) gave birth via the vaginal route and 626 (50.4%) delivered via C-section. The mean milk concentrations of iron, copper, zinc, and manganese in the milk of women delivering via the vaginal route were higher than those in the milk of women delivering via C-section; only the copper concentration differences were statistically significant, after adjusting for confounding factors (p = .023). Conclusion: Delivery mode impacts breast milk concentrations of essential trace elements, with vaginal delivery being associated with higher essential trace element concentrations than C-sections.