Human milk composition is associated with maternal overweight/obesity and low milk supply, with implications for infant weight outcomes: a cross-sectional study.

BACKGROUND

Low milk supply (LMS) is a major barrier to exclusive and continued lactation. Maternal factors such as overweight/obesity (OW) and gestational diabetes mellitus may contribute to LMS and alter human milk (HM) composition, affecting infant growth.

OBJECTIVES

This cross-sectional study examined associations of HM components with LMS and maternal factors, and relationships between infant milk intake and weight outcomes.

METHODS

Twenty-four-hour milk production was measured at 1-6 mo postpartum using the test-weigh method. HM samples, demographic, obstetric, and infant data were collected from 225 participants. Macronutrients (fat, protein, lactose, and glucose) and hormones (estrone, estradiol, progesterone, leptin, adiponectin, and insulin) were analyzed.

RESULTS

Maternal OW was associated with higher concentrations of HM fat [β = 5.2; 95% confidence interval (CI): 6.5 × 10-3, 10.4], leptin (β = 197.4; 95% CI: 125.8, 269.1), insulin (β = 5.9; 95% CI: 2.5, 9.2), and higher infant intake of leptin (β = 135.9; 95% CI: 86.3, 185.4) and insulin (β = 3.2; 95% CI: 1.3, 5.0). In the LMS group, despite higher concentrations of HM protein, lactose, insulin, estrone, and progesterone, infant total intakes of fat (β = -9.5; 95% CI: -1.4, -5.4), carbohydrates (β = -6.0; 95% CI: -10.2, -1.8), estrone (β = -9.9; 95% CI: -14.5, -5.4), estradiol (β = -3.5; 95% CI: -5.1, -1.9), leptin (β = -55.9; 95% CI: -109.0, -2.7), and adiponectin (β = -3.9; 95% CI: -6.0, -1.7) were lower. Additionally, infant carbohydrates (β = 11.5 × 10-3; 95% CI: 4.6 × 10-3, 18.4 × 10-3), energy (β = 1.0 × 10-3; 95% CI: 0.3 × 10-3, 1.6 × 10-3), and 24-h total intakes (β = 1.7 × 10-3; 95% CI: 1.1 × 10-3, 2.4 × 10-3) were positively associated with infant weight-for-age z-score.

CONCLUSIONS

Maternal OW influences HM composition and infant milk intake. LMS impacts infant weight gain by limiting milk volume, underscoring the importance of timely LMS detection to ensure adequate infant nutrition.