RESUMO
AIM: We aimed to evaluate the addition of fetal thigh circumference (TC) to other ultrasound parameters to predict fetal weight compared to two standard formulae (Hadlock's and Vintzileos methods). METHODS: We conducted this prospective study on pregnant women between November 2018 and September 2019. The actual fetal weight was estimated within 48 h of delivery; then, it was compared to the estimated fetal weight by ultrasound. We used the Statistical Package for the Social Sciences (SPSS) software version 20.0 to perform the statistical analysis. RESULTS: A total of 123 pregnant women, with a mean age of 26.68 (5.24) years and a mean gestational age of 38.78 (0.85) weeks, were included in our study. We detected a significant positive correlation between different ultrasound parameters and actual weight (all p ≤ 0.001). The highest correlation was observed between TC and actual fetal weight (r = 0.685). Regarding both formulae, the correlation coefficient was higher in the Vintzileos formula than the Handlock formula (0.976 vs. 0.823). Our linear regression analysis showed that fetal TC could be an indicator for estimating fetal weight (p < 0.001). There was a statistically significant difference between the actual weight and the weight estimated by the Hadlock formula (p < 0.001). We detected no statistically significant difference between the estimated TC by ultrasound and the actual TC (p = 0.0602). CONCLUSION: Fetal TC can help accurately measure fetal birth weight when incorporated with other fetal parameters. The inclusion of fetal TC assessment in routine ultrasound examination is suggested to improve the birth estimates.