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.本研究旨在探讨分娩方式（阴道分娩或剖宫产（cesarean section，简称C-section））是否会影响母乳中四种必需微量元素（铁、铜、锌、锰）的浓度。 方法：本研究纳入中国7个不同地区的7家医院的分娩产妇。每位受试者于产后3~5天采集母乳样本，用于检测上述四种微量元素的浓度。对比阴道分娩与剖宫产产妇的母乳微量元素浓度差异。 结果：本研究共纳入1243名产妇，其中617名（49.6%）经阴道分娩，626名（50.4%）行剖宫产术。阴道分娩产妇的母乳中铁、铜、锌、锰的平均浓度均高于剖宫产产妇；在校正混杂因素后，仅铜浓度的组间差异具有统计学意义（p=0.023）。 结论：分娩方式会影响母乳中必需微量元素的浓度，阴道分娩产妇的母乳必需微量元素浓度高于剖宫产产妇。