Background: Accurate foetal birth weight estimate is crucial for detecting growth limitation, preterm, and situations where clinical decisions affecting labour induction or delivery mode need to be made. This research study was conducted to determine the accuracy of predicting prenatal weight using foetal thigh circumference (TC). Patients and methods: Between November 2018 and September 2019, we performed a cross-sectional study of pregnant women. We included single intrauterine pregnant women with no complications, and who delivered within 48 hours after examination, with gestational ages ranging from 38 to 41 weeks. Within 48 hours following birth, the true foetal weight was estimated. Results: We included 123 pregnant women, with a mean gestational age of 38.78 (SD 0.85) weeks and a mean age of 26.68 (SD 5.24) years. Of them, 21.1% were nulliparous. We found an ultrasound parameter-to-actual-weight association that was statistically significant in favour. The greatest association between actual foetal weight and TC (r =0.685; p<0.001). Simple linear regression showed that TC is a predictor of estimated fetal weight (B =153.5, p< 0.001). Between estimated foetal weight and actual weight, as well as between estimated and real TC, we found no discernible difference (p values 0.398 and 0.06, respectively). Conclusion:When used in conjunction with other fetal measures, the foetal thigh circumference may aid in the precise computation of fetal birth weight. To increase the accuracy of birth estimations, regular ultrasound examinations should include fetal thigh circumference measurement.

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.