Head Circumference within the Normal Range and Neurodevelopmental Outcomes in Preterm Infants

Abstract

Objective We sought to determine if variation in head circumference (HC) within the range of normal (5th–10th and 90th–95th percentile) is associated with poor neurodevelopmental outcomes (NDO), which defined as mild or moderate delay by Bayley II psychometrics (BSID-II). Study Design This is a secondary analysis of a randomized controlled trial assessing the benefits of magnesium for the prevention of cerebral palsy. Fetuses with a normal HC at birth defined as within 5th to 95th percentile were included. NDO were assessed at age 2 with BSID-II. Moderate delay was defined as a score <70 and mild delay as <85. HC was classified as small normal (5th–10th percentile), normal (10th–90th percentile), and large normal (90th–95th percentile). Logistic regression models adjusted for confounding. Linear regression models estimated the impact for every 1 cm of change in HC. Results Of 1,236 included infants, 111 (8%) had small normal HC; 1,058 (85%) had normal HC; and 67 (5%) had large normal HC. Baseline characteristics were similar between groups. There was no association with changes in HC within the range of normal and developmental indices. When considered as a continuous variable, every 1 cm increase in HC was also not associated with a significant change in developmental indices. Conclusion Within the normal range (5th–95th percentile), changes in HC did not correlate with changes in NDO at 2 years as measured by Bayley II scales. Key Points