Risk of cerebral palsy in term-born singletons according to growth status at birth
An excess risk of cerebral palsy (CP) has been reported in children of both low and high birthweight. However, the risk associated with deviations from the mean of other anthropometric measurements has been less well studied. The aim of our study therefore was to determine the association between size measurements at birth and incidence of CP in singletons born at term.
Standard deviation z-scores for weight, length, head circumference, and ponderal index at birth of term-born singletons born between 1996 and 2006 were calculated using data from the Medical Birth Registry of Norway. The measurements of 398 children with CP recorded in the Cerebral Palsy Registry of Norway were compared with those of 490 022 typically developing infants.
Children with low birthweight (p<0.001; <10th centile) as well as low and high z-scores for length (p<0.001 and p<0.001) and head circumference (p<0.001 and p<0.003; <90th centile) had an excess risk of CP, in particular of spastic bilateral CP. Spastic unilateral CP was associated only with low z-scores, whereas children with the greatest body length and largest head circumference, but with low ponderal index, had an excess risk of spastic quadriplegic and dyskinetic CP.
Our results are consistent with the notion that most subtypes of CP are due to antenatal factors leading to poor intrauterine growth, whereas CP in children who were large at birth is more likely to be due to intrapartum factors.