Fetal weight estimates in late pregnancy with emphasis on macrosomia

The effectiveness of three methods (Shepard et al, Hadlock et al, and Hansmann) for estimating fetal weight was evaluated in 150 patients at greater than 36 weeks menstrual age. All infants were greater than 2,500 at birth. Only the method of Hadlock et al did not systematically underestimate birth weight. When separate weight subclasses (2,500 to 4,999 g) were examined, the method of Hadlock et al showed better consistency. All models, however, had significant underestimates for the largest subclasses, 4,000 to 4,999 g. The ability to predict the macrosomic infant (greater than or equal to 4,000 g) was only slightly better using the method of Hadlock et al than by the formula of Shephard et al.