Effect of Vaginal Delivery on Lactose Content of Human Milk

Objective: The macronutrients of human milk are considered essential nutritional sources in the first few months of a newborn's life. The present study aimed to investigate the effect of delivery mode on the macronutrients of human milk. Methods: This retrospective cohort study was conducted on 102 women who gave birth by cesarean section or vaginal delivery between September 2019 and November 2019. The participants were requested to provide their milk samples on day 15 +/- 1 after childbirth. Results: There were no significant differences between the two groups (cesarean and vaginal delivery) regarding the sociodemographic characteristics and intake of fat, carbohydrate, protein, and energy. The lactose level was significantly higher in women who gave birth by vaginal delivery (adjusted mean difference, 1.2 (95 % CI 0.02- 1.82)). For other macronutrients, there were no statistically significant differences between the two groups. Conclusion: The vaginal delivery might influence the mature milk lactose level.