Repositioning early head circumference to predict catch-up growth in SGA infants

Early identification of catch-up growth (CUG) in small-for-gestational-age (SGA) infants is critical. Head circumference at the first postnatal visit may capture distinct dimensions of early growth programming. We investigated its association with time to weight and length CUG.

A retrospective cohort of 1338 SGA infants with an initial visit <60 corrected days was followed to 2 years. Time-to-CUG was analyzed using Cox models; nonlinearity was assessed via restricted cubic splines and segmented regression.

Head circumference Z-score was independently associated with both outcomes. For weight CUG, a non-linear relationship was observed (P = 0.006), with a threshold at -2.42 (below: HR 1.74, 95% CI 1.18, 2.58; above: HR 1.59, 95% CI 1.44, 1.75). For length CUG, the relationship was linear (HR 1.74, 95% CI 1.59, 1.90). Preterm infants showed a stronger association for weight CUG (P = 0.01).

Early head circumference Z-score independently predicts CUG timing in SGA infants, exhibiting a non-linear threshold effect for weight recovery and a linear association for linear growth. This routinely available measure offers a pragmatic tool for risk stratification in SGA follow-up.

Early postnatal head circumference measured at the first child health visit (<60 days) independently predicts catch-up growth timing in SGA infants, providing a pragmatic, routinely available tool for risk stratification in follow-up protocols. A non-linear threshold for weight catch-up was identified at Z-score -2.42 (HR 1.74 below; HR 1.59 above), pinpointing a high-risk subgroup requiring intensive monitoring, while the linear association with length catch-up was consistent across all head sizes. Preterm SGA infants showed stronger weight catch-up associations (P = 0.01), highlighting their vulnerability and need for prioritised intervention.