Comparative Study of Various Methods of Fetal Weight Estimation in Term Pregnancy

Objective: The goal of this study was to evaluate the various methods of estimating fetal weight in term pregnancy and to determine their relative accuracy in predicting the same in different weight categories. Materials and methods: The study was conducted at Department of Obstetrics and Gynecology, Medical College and Hospital, Kolkata from 1st July 2009 to 30th June 2010. It was a prospective cohort type of study covering 500 pregnant women at term. Parameters studied (a) average error (gm) in different birth weight categories, (b) standard deviation of prediction error in each birth weight category. Results: Ultrasonography was found to have least standard deviation closely followed by the two clinical methods proposed by Johnson and Dare. The average positive predictive value of different methods in our study was 42.2, 70.9, 80.5 and 76% for Dawn’s, Johnson’s, Dare’s formulas and USG respectively. Conclusion: Easily measurable obstetric parameters with simple instruments requiring minimal manpower training are equally accurate as USG in predicting fetal weight.