Background

Despite recent advances in nutrition practice in the neonatal intensive care unit, infants remain at high risk for growth restriction following preterm birth. Additionally, optimal values for macronutrient administration, especially lipid intake, have yet to be established for preterm infants in the extrauterine environment.

Methods

We studied preterm infants born at very low-birth weight (VLBW, <1500 g) and ≤32 weeks' gestation. Cumulative macronutrient (carbohydrate, lipid, protein, energy) intake in the first 2 and 4 weeks of life was compared with total and regional brain volumes on magnetic resonance imaging (MRI) obtained at term-equivalent age. Preterm infants had no structural brain injury on conventional MRI.

Results

In a cohort of 67 VLBW infants, cumulative lipid intake in the first 2 weeks of life was positively associated with significantly greater cerebellar volume (β = 95.8; P = .01) after adjusting for weight gain, gestational age at birth, and postmenstrual age at MRI. Cumulative lipid (β = 36.1, P = .01) and energy (β = 3.1; P = .02) intake in the first 4 weeks of life were both significantly associated with greater cerebellar volume. No relationship was seen between carbohydrate or protein intake in the first month of life and cerebral volume at term-equivalent age.

Conclusion

Early cumulative lipid intake in the first month of life is associated with significantly greater cerebellar volume by term-equivalent age in very premature infants. Our findings emphasize the importance of early, aggressive nutrition interventions to optimize cerebellar development in VLBW infants.

Background The third trimester of gestation is a crucial phase of rapid brain development, but little has been reported on the trajectories of cerebral blood flow (CBF) in preterm infants in this period. Purpose To quantify regional CBF in very preterm infants longitudinally across the ex utero third trimester and to determine its relationship with clinical factors associated with brain injury and premature birth. Materials and Methods In this prospective study, very preterm infants were enrolled for three longitudinal MRI scans, and 22 healthy full-term infants were enrolled for one term MRI scan between November 2016 and February 2019. Global and regional CBF in the cortical gray matter, white matter, deep gray matter, and cerebellum were measured using arterial spin labeling with postlabeling delay of 2025 msec at 1.5 T and 3.0 T. Brain injury and clinical risk factors in preterm infants were investigated to determine associations with CBF. Generalized estimating equations were used to account for correlations between repeated measures in the same individual. Results A total of 75 preterm infants (mean postmenstrual age [PMA]: 29.5 weeks ± 2.3 [standard deviation], 34.9 weeks ± 0.8, and 39.3 weeks ± 2.0 for each scan; 43 male infants) and 22 full-term infants (mean PMA, 42.1 weeks ± 2.0; 13 male infants) were evaluated. In preterm infants, global CBF was 11.9 mL/100 g/min ± 0.2 (standard error). All regional CBF increased significantly with advancing PMA (P ≤ .02); the cerebellum demonstrated the most rapid CBF increase and the highest mean CBF. Lower CBF was associated with intraventricular hemorrhage in all regions (P ≤ .05) and with medically managed patent ductus arteriosus in the white matter and deep gray matter (P = .03). Mean CBF of preterm infants at term-equivalent age was significantly higher compared with full-term infants (P ≤ .02). Conclusion Regional cerebral blood flow increased significantly in preterm infants developing in an extrauterine environment across the third trimester and was associated with intraventricular hemorrhage and patent ductus arteriosus. © RSNA, 2021 Online supplemental material is available for this article.