Incidence and two-year neurodevelopmental outcomes of small-for-gestational-age preterm infants: how do they relate to using different neonatal anthropometric charts?

Background: The effect of different neonatal anthropometric charts on the incidence and neurodevelopmental outcomes at two years (Y) corrected age of small-for-gestational-age (SGA) preterm infants has still not been fully explored.

Methods: All preterm infants with a gestational age (GA) between 24.0 and 31.6 weeks (W), born from Jan-2004 to Dec-2017 in the Marche region (Italy) were studied. Intergrowth-21, Beeby, Fenton, and Bertino anthropometric charts were used to classify infants with a birth weight less than 10 centile as SGA. Disabilities and neurodevelopmental scores assessed by Bayley-III Test were recorded at the 2Y follow-up visit.

Results: One thousand one hundred forty-seven preterm infants were evaluated. The incidence of SGA was significantly different among the study charts (from 12.9 to 17.5%). Nine hundred and twenty-seven study infants were assessed for neurodevelopmental outcomes at 2Y corrected age. The incidence of SGA with moderate cognitive impairment (COG Score: 70-84) and mild neurodevelopmental disability (NDD) were significantly different between the Intergrowth-21 and Bertino charts (31.7% vs. 19.6%, P=0.042; 30.8 vs. 19.2%, P=0.036; respectively). A statistically significant difference in COG Score was found between SGA preterm infants overlapping in all study charts and those classified as SGA only by the Intergrowth-21 chart (89.1±15.7 vs. 99.2±19.8; P=0.038).

Conclusions: In a large cohort of preterm infants with a GA between 24.0 and 31.6W, the incidence and neurodevelopmental outcomes at 2Y corrected age of SGAs were significantly different depending on the anthropometric charts. These differences, albeit small, should be considered both in clinical practice and trials on SGA preterm infants.