359 - Breast milk exposure and neurodevelopmental outcomes in very preterm infants

Publication Number: 3346.359

Émilie Harnois, CHU de Québec - Université Laval, Québec, PQ, Canada; Audrey-Anne Milette, CHU de Québec - Université Laval, Québec, PQ, Canada; Etienne Pronovost, CHU de Québec-Université Laval, Quebec City, PQ, Canada; Narcisse Singbo, CRCHU de Québec - Université Laval, Québec, PQ, Canada; Mireille Guillot, CHU de Québec - Université Laval, Quebec, PQ, Canada; Audrey Hébert, CHU de Quebec, Quebec city, PQ, Canada

Background: Despite advances in neonatal care, very preterm infants remain at high risk of lifelong neurodevelopmental impairment. Breast milk (BM) is promoted as a neuroprotective strategy, but existing studies are limited by inconsistent exposure definitions and mixed results.

Objective: To evaluate the association between BM exposure in the NICU and neurodevelopmental outcomes at 18-22 months' corrected age in very preterm infants.

Design/Methods: We retrospectively studied infants born < 29 weeks' gestation or < 1000g between 2018 and 2022 using data from the Canadian Neonatal Network and the Canadian Neonatal Follow-Up Network. Infants with major anomalies, death, or loss to follow-up were excluded. Neurodevelopment was assessed with Bayley-III/IV. Daily BM, donor milk and formula intakes were extracted from charts until 36 weeks' postmenstrual age and at discharge. BM exposure was analyzed categorically (0%, < 50%, 50-99%, 100%) and continuously (per 10 mL/kg/day increase). Associations between BM categories and cognitive and language scores were compared using ANCOVA, and linear regression with Generalized Estimating Equations for motor scores. The associations between BM continuous exposure and neurodevelopmental scores were assessed with multivariable linear regression and correlation models. All models were adjusted for confounding variables (maternal age, education and ethnicity, gestational age, sex, small for gestational age, severe intraventricular hemorrhage, necrotizing enterocolitis and periventricular leukomalacia) and multiple comparisons, when appropriate.

Results: A total of 157 infants were included (mean GA 26.8 weeks (SD 1.4), mean birth weight 933.6g (SD 234)). Compared to infants who received no BM, exclusive BM intake was associated with higher cognitive score (mean difference 15.2 [95% CI 1.3 to 29.0], P=0.03) and motor score (mean difference 14.8 [95% CI -0.2 to 29.9], P=0.05). In continuous models, each 10 mL/kg/day increase in BM intake was associated with higher cognitive score (0.8-point increase [95% CI 0.2 to 1.4, P=0.01) and motor score (0.9-point increase, [95% CI, 0.2 to 1.6], P=0.01). Although not significant, higher language score were also observed with higher BM intake (0.6-point increase [95% CI -0.1 to 1.3], P=0.07). These results were consistent when using correlation models.

Conclusion(s): In neonates born very preterm, greater exposure to maternal BM was independently associated with improved cognitive and motor outcomes at 18-22 months, with a dose-response relationship observed. These findings support BM promotion as a modifiable strategy to optimize neurodevelopment.

Table 1. Characteristics of the Mothers and their Infants
a: Unless otherwise indicated.

Figure 1. Association Between Maternal Breast Milk Exposure Categories and Bayley Cognitive, Language and Motor Scores
Bayley-III/IV outcomes at 18-22 months' corrected age by BM exposure. The box reflects the interquartile range, the middle line the median, and the circle the mean. Whiskers indicate the minimum and maximum, excluding outliers. Only statistically significant adjusted P-values are shown.

Table 2. Association Between Maternal Breast Milk Exposure per 10 ml/kg/day and Bayley Cognitive, Language and Motor Scores
BM: Breast milk.
a: Data estimated by a generalized estimating equations linear regression model adjusted for maternal age, education, and ethnicity, gestational age, sex, small for gestational age, severe intraventricular hemorrhage, necrotizing enterocolitis, and periventricular leucomalacia.
b: Data estimated by a Pearson coefficient model adjusted for maternal age, education, and ethnicity, gestational age, sex, small for gestational age, severe intraventricular hemorrhage, necrotizing enterocolitis, and periventricular leucomalacia.
c: Data estimated by a Spearman coefficient model adjusted for maternal age, education, and ethnicity, gestational age, sex, small for gestational age, severe intraventricular hemorrhage, necrotizing enterocolitis, and periventricular leucomalacia.