Placental lesions and abnormal neurocognitive function at school age in extremely low-birth weight infants

We read with much interest the paper by Redline and colleagues [1] about placental lesions as predictors of neuromotor and cognitive outcome at school age in extremely low–birth weight infants (ELBWI). They found that lesions associated with maternal underperfusion were most closely linked with cerebral palsy, while those involving the fetal vasculature, villous edema, and severe-grade 3/3 fetal inflammation were more closely related to abnormal results in neurocognitive tests measuring global cognitive ability and executive functioning at school age. The reason why maternal vascular lesions should be more strongly linked to motor function and fetal vascular lesions to neurocognitive abnormalities has not yet been clarified; however, the correlations between histological chorioamnionitis (HCA) and adverse neurodevelopmental outcome of ELBWI are currently a major focus of research [1–3]. We are studying the relationship between preterm HCA, graded and scored according to the method of Redline and colleagues [1], and neuromotor and neurocognitive development in a cohort of 102 premature neonates (,32 weeks of gestation) admitted to the level III neonatal intensive care unit of the Department of Pediatrics of Padua University (Padua, Italy) between January 1998 and December 2002. We found that the preschool age intelligence quotient, measured by the Wechsler Preschool and Primary Scale of Intelligence, and neuropsychological functions were not statistically different in HCA and non- HCA groups. Instead, executive functions, Tower of London, and Elithorn Perceptual Maze Test werebelow 2 standard deviations in 16% of HCAversus 5% of non-HCA subjects. Unlike Redline and colleagues, we did not separate infant subgroups with distinct HCA pathologic characteristics as predictors of abnormal cognitive and/or executive functions. However, our data indicate that premature infants with HCA have high rates of neurodisability at preschool age, which indicates the need to investigate LBWI subgroups with distinct pathological and perinatal characteristics and to extend the follow-up at school age.