Neurodevelopmental Outcome up to 5 Years after Isolated Mild Non-Cystic White Matter Injury in Very Preterm Infants.

Introduction: Mild non-cystic white matter injury (WMI) is commonly detected on MRI in very preterm infants, but its prognostic significance remains uncertain. We assessed neurodevelopmental outcomes up to 5 years in infants with isolated mild non-cystic WMI on term-equivalent MRI compared with those without brain injury.

Methods: In this population-based retrospective cohort study, infants born <32 gestational weeks in Tyrol, Austria (2011-2018), were included. MRI was performed at term-equivalent age. Infants with isolated mild non-cystic WMI (Kidokoro PVL grade 1-2) and those without brain injury were analysed. Neurodevelopmental outcomes were assessed at 12 and 24 months' corrected age using the Bayley Scales and at 5 years using standardized cognitive tests (WPPSI-III, KABC-II, SON-R) and the MABC-2.

Results: Of 363 infants, 35 (9.6%) had isolated mild non-cystic WMI. Median cognitive and motor scores were within the normal range in both groups at all time points, with no significant differences, although cognitive scores were numerically higher in the WMI group at 12 months (p = 0.087). Rates of developmental delay (<85) and impairment (<70) did not differ between groups. All infants with isolated mild non-cystic WMI were born at ≥28 gestational weeks; findings were consistent in this subgroup.

Conclusion: Isolated mild non-cystic WMI was not associated with adverse neurodevelopmental outcomes up to 5 years. In settings with routine MRI at term-equivalent age, these findings suggest that isolated mild non-cystic WMI may have limited prognostic value and should not be overinterpreted as markers of adverse outcome in clinical counselling.