Reviewing birthweight standards.

The standardization of birthweight for gestational age, taking into account sex of infant and maternal height and weight, is clinically useful and essential for some research purposes. In Britain, the most commonly used standards for singletons are those derived from Thomson et al. (1968) from a series of births to women in Aberdeen between 1948 and 1964. The present study starts with the observation that the present population of births in Aberdeen is different. This prompted work to 'update' the standards at least for research purposes, and in so doing a number of problems have been encountered which complicate the task of developing universally applicable standards.