Punctate White Matter Abnormality in Moderate-to-Late Preterm Infants

Moderate-to-late preterm (MLP) infants contribute to the greatest proportion of preterm children with neurodevelopmental impairments. White matter injury (WMI) is common and predicts adverse outcomes in very preterm (VP) infants. However, little is known about white matter abnormality (WMA) in MLP infants. We investigated the burden and distribution of WMA in MLP infants.

MLP infants were recruited from a randomized trial on neonatal nutrition and a prospective observational cohort in New Zealand, and underwent brain magnetic resonance imaging (MRI) soon after birth and at term-equivalent age (TEA). WMA was manually segmented using an established method. Total and regional WMA volumes and percentage of WMA to total cerebral volume were calculated. Probabilistic WMA maps were generated and compared with WMI in VP infants and term infants with congenital heart disease.

Of 101 infants (32 females), 40 (39.6%) had WMA on at least 1 scan. In 37 infants with WMA who had both scans, WMA was less visible in 22 (59.5%) or undetectable in 7 (18.9%) infants with a mean reduction of 72.7 ± 207.5 mm³ in WMA volume from early-life to term. Infants with and without WMA had mostly comparable pregnancy and neonatal characteristics. Probabilistic maps demonstrated a characteristic WMA topology, with most lesions in posterior followed by central and anterior regions. Trigonal areas were vulnerable across neonatal populations.

WMA is much more common in MLP infants than previously reported and occurs in a characteristic topology. WMA may be missed on TEA MRI, and its relationship with outcomes in MLP infants warrants attention. ANN NEUROL 2025;98:329-340.