Do gender and birth height of infant affect calorie of human milk? An association study between human milk macronutrient and various birth factors.

Objective: The purpose of this study is to analyze the macronutrient of human milk (HM) and to find out the various maternal-infantile factors that can affect HM composition.

Methods: 478 HM samples were collected from healthy and exclusively breast-feeding mothers who delivered healthy term neonates within 3 months. Macronutrient of the samples was analyzed and the birth data were collected.

Results: In multivariate logistic regression analysis, various maternal-infantile factors were found to be associated with HM composition changes; higher fat: cesarean section (OR = 2.47, p < 0.001) and birth height (OR = 0.84, p = 0.004); higher protein: postpartum age (OR = 0.89, p < 0.001); higher carbohydrate: vaginal delivery (OR = 0.50, p = 0.005) and female infant (OR = 0.56, p = 0.012); higher calorie: postpartum age (OR = 0.95, p = 0.003), female infant (OR = 0.33, p = 0.017), and birth height (OR = 0.74, p < 0.001). Female infant (OR = 0.36, p = 0.029), birth height (OR = 0.73, p = 0.001), and postpartum age (OR = 0.95, p = 0.005) were found as independent risk factors for higher HM calorie.

Conclusion: Various maternal-infantile factors were found to affect HM composition. Interestingly, delivery mode, gender of infant, and birth height were associated with changes in HM macronutrient as well as postpartum age.