Which formula should be used in Ireland to estimate fetal weight?

In order to determine which formula most accurately predicts weight in Irish infants we performed a prospective study on 162 mothers within one week of delivery. Actual weights were compared with estimated weights derived from the formulae of Shepard; Hadlock; Birnholtz; Deter and Campbell. Overall the Deter formula gave the closest approximation of birth weight. All the formulae became increasingly inaccurate in the larger infants i.e. > 4 kg. However in infants of average weight the Campbell formula, which is based on a single measurement (A.C), is as good as any.