ABSTRACT Background and aims There is a lack of evidence on the value of head circumference (HC) as a screening measure. We aimed to describe the incidence of head centile shifting and the relationship between extremes of head size and later neurodevelopmental problems in the Avon Longitudinal Study of Parents and Children (ALSPAC). Methods HC was measured routinely at 2, 9 and 18-24 months, and by researchers at ages 4,8,12 and 18 months. WISC IQ was measured in research clinics at age 8 for all. Neurocognitive diagnoses (NCD) were identifed from chart review. Results There were 10,851 children with 2 or more head measures. At each age 2-3% were <-2SD or >2SD, but most only at one age. More than 15% children showed centile shifts, but less than a third were sustained at subsequent measurements. Only 0.5% showed a sustained shift beyond the normal range. Children with consistently small heads were up to 7 times more likely to have an NCD, but 85% children with small heads had no NCD, while 93% children with NCD had head SD scores within the normal range. Conclusions Centile shifts within the normal range occur commonly and seem mainly to reflect measurement error. This makes robust assessment of the head trajectory difficult and may result in many children being investigated unecessarily. Extreme head size is neither specific nor sensitive for detecting NCD, suggesting that routine measurement of HC is unhelpful.
- head circumference, hydrocephalus, neurodevelopment, screening, ALSPAC