Estimation of Fetal Weight by Clinical Method &  Ultrasonography & It's Correlation with Actual Birth Weight In Term Pregnancy

Background: Accurate estimation of fetal weight (EFW) is a crucial component of prenatal care, guiding decisions regarding delivery timing, mode of delivery, and neonatal management. While clinical methods such as Dare’s formula are widely used, ultrasonography (USG) is considered the gold standard due to higher precision. Objectives: To evaluate the accuracy of fetal weight estimation by clinical methods (Dare’s formula) and USG and to assess their correlation with actual birth weight in term pregnancies. Methods: This prospective observational study included 390 term pregnant women admitted for delivery at Pacific Medical College and Hospital, Udaipur, Rajasthan, India. Fetal weight was estimated clinically using Dare’s formula and by USG (Hadlock’s formula) and compared with actual birth weight measured immediately after birth. Maternal, obstetric, delivery, and neonatal characteristics were recorded. Statistical analyses included mean difference, mean error, standard deviation, and Pearson correlation coefficient. Results: The study population comprised predominantly women aged 26–40 years (75%) and multigravidae (69.2%). Dare’s formula tended to overestimate fetal weight in 218 cases, underestimate in 105 cases, and matched actual birth weight in only 4 cases. In contrast, USG estimates were closer to actual birth weight, with 152 overestimations, 215 underestimations, and a large proportion showing exact agreement. USG demonstrated superior accuracy across all ranges (±50 g: 19% vs. 9%; ±200 g: 80% vs. 42%; ±500 g: 100% vs. 88%). Mean difference from actual birth weight was much smaller for USG (30.6 g) than Dare’s formula (144.7 g). Mean error per kg was lower with USG (47 g/kg vs. 95 g/kg), and the Pearson correlation confirmed a very strong correlation with actual birth weight (r = 0.942) compared to Dare’s formula (r = 0.79). Vaginal delivery occurred in 53.8% of cases, and most neonates had good Apgar scores at 1 and 5 minutes.