Background: Accurately estimating fetal weight facilitates optimal care planning. Traditionally, formulas using biometric parameters like the biparietal diameter (BPD) and femur length (FL) guided assessments. More recently, ultrasound measurements of the fetal thigh circumference and fractional thigh volume emerged as promising alternative predictors.   
Aim: To evaluate fetal thigh circumference & fractional thigh volume's accuracy in predicting birth weight.   
Methods: We recruited 60 women in their third trimester with singleton pregnancies, excluding cases with anomalies or gestational age discrepancies. Standardized ultrasound biometry between 37-40 weeks measured parameters including BPD, abdominal circumference (AC), head circumference (HC), FL, thigh circumference (TC) & thigh volume (TVol). Estimates utilized Hadlock's, Vintzileos', Lee formulas. Actual weights were recorded post-delivery. 
Results: The average age of participants was 29.38 ± 7.56 years. Gestational age varied among 37& 40.29 weeks. Actual birth weight mean was 3552.60 ± 689.87 grams. Estimated weights: Hadlock's - 3366.38 ± 590.82 grams, p<0.001; Vintzileos' - 3299.60 ± 630.95 grams, p=0.003; Lee 1 formula - 3693.07 ± 778.83 grams, p<0.001; Lee 2 - 3596.52 ± 754.27 grams, p=0.012. No significant variance among estimated & actual TC (pgreater than0.05). Strong positive correlations between actual weight and all estimates (p<0.001), highest for Lee 2 (r=0.985) and Lee 1 formula (r=0.984). Multiple regression identified Lee 1 and Lee 2 formula as significant predictors (p=0.040, 0.002). ROC analysis found optimal sensitivity/specificity for TVol (100/95.8%), Hadlock's (100/93.7%), Lee 1 formula (100/95.8%), Lee 2 (100/95.8%) but reduced for Vintzileos' (75/87.5%).
Conclusion: Our study revealed that Lee 2 formula proved most clinically reliable. TC and TVol also strongly correlated with actual weight, indicating reliability. TVol exhibited high diagnostic value.