Background and Objectives: Fetal weight is one of the greatest factors, determining the survival of the fetus. Ultrasound study presents a very important tool in modern day obstetrics. Accurate assessment of fetal weight is mandatory for obstetric management particularly at term. Present study is a prospective observational study comparing the fetal weight estimation by clinical method using Johnson’s formula and ultrasound method using Hadlock’s formula at term and its accuracy with the actual birth weight. Methods: Present study was a prospective observational study conducted in 300 term pregnant women. Expected fetal weight was estimated by measuring symphysio fundal height clinically using Johnson’s formula and ultrasonographically using Hadlock’s formula. Both the weights were compared with actual birth weight. Statistical test were done using student-t test and chi square test. Results: The mean birth weight of Hadlock’s formula, 2942.57 gms, was closest to mean of actual birth weight, 2958.01 when compared to Johnson’s formula mean birth weight 3046.95. The difference between mean birth weights of Hadlock’s and Johnson’s formula with actual birth weight being 15.433 gms and 88.947 gms respectively. The mean error and standard deviation from actual birth weight are least with Hadlock’s formula compared to Johnson’s formula. Conclusion: Birth weight is a key variable affecting fetal and neonatal morbidity, particularly in preterm and small for date babies. In addition, it is of value in the management of breech presentations, diabetes mellitus, trial of labour, macrosomic foetuses and multiple births. Of the two methods studied, ultrasonographic method, i.e., Hadlock’s formula has better predictable results in fetal weight estimation, compared tho clinical method, i.e., Johnson’s formula.

Keywords: Ultrasound, Hadlock’s formula, Johnson’s Formula, Symphysio Fundal Height, Actual Birth Weight.