(P07-044-23) Maternal and Preterm Infant Predictors of Human Milk Oligosaccharide and Lactoferrin Concentrations

Objectives: Among preterm infants, human milk exposure is beneficial for brain development and immune response. Human milk oligosaccharides (HMOs) and lactoferrin (Lf) are bioactives that may underlie such benefits. Yet, there is limited data on clinical factors that influence HMO and Lf composition. Our aim was to assess associations between maternal and preterm infant characteristics and mean HMO and Lf concentrations in maternal milk.

Methods: Participants were mothers of very preterm infants (gestational age, GA < 32 weeks) who had ≥2 milk samples analyzed for HMO (n=72) and Lf (n=58) concentrations. HMO analyses were focused on secretor mothers (2’-fucosyllacose present in milk). Exposures were maternal and infant characteristics: advanced maternal age (≥35 years), extreme preterm birth (GA < 28 weeks), overweight/obese pre-pregnancy BMI (≥25 kg/m2), small for GA infant ( < 10%ile), and maternal race/ethnicity. Outcomes were mean HMO (µg/mL) and Lf (mg/mL) concentrations over two timepoints (Time 1: HMO 13.3 ± 7.5d, Lf 16.4 ± 7.2d. Time 2: HMO 52.6 ± 25.7d, Lf 25.9 ± 7.4d). We used multivariate linear regression to estimate associations between clinical characteristics and mean HMO or Lf concentrations. All exposures were included in the model to assess each controlling for the others.

Results: Mean pre-pregnancy BMI was 29.8±7.9 kg/m², and 64% were classified as overweight/obese. Fourteen percent had at least one SGA infant, and 17% self-identified as Hispanic. Mean GA was 28.5±2.2 weeks with birthweight 1109±391 g. Milk of mothers who had advanced maternal age had 137 µg/mL (95% CI: -240, -35 µg/mL) lower mean DSLNT (disialyllacto-N-tetraose) and 2070 µg/mL (95% CI: -3710, -430 µg/mL) lower mean total HMO compared to milk of mothers < 35 years. Milk of Hispanic (vs non-Hispanic) mothers had 190 µg/mL (95%CI: 17, 364 µg/mL) higher mean DSLNT. Clinical characteristics were not significantly associated with mean Lf levels.

Conclusions: Among secretor mothers of nutritionally vulnerable very preterm infants, advanced maternal age was associated with lower levels of total HMO and DSLNT, an HMO linked to necrotizing enterocolitis. Non-Hispanic ethnicity was also associated with lower DSLNT. These maternal characteristics may help identify infants at risk for low human milk bioactive exposure during neonatal hospitalization.

Funding Sources: Allen and Gates Foundations