Updated birth weight centiles for England and Wales.

We have constructed and validated updated birth weight-for-gestational age centiles using a contemporary sample of births occurring in England and Wales. The benefits of these updated centiles will be first to assist the national surveillance of perinatal mortality programme by improving the identification of the proportion of stillbirths and neonatal deaths affected by intrauterine growth restriction and, second, to aid clinicians by more accurately identifying babies who require increased monitoring in the period immediately following birth.