Sonographic estimation of fetal weight in term pregnant women

Introduction: Deviation from normal fetal weight and growth contribute to morbidity and mortality in the perinatal period. Over 50 formulas for EFW (estimated fetal weight) have been published and yet the ideal formula has not been determined. The objective of this study was to evaluate the accuracy of sonographic estimation of fetal weight using Hadlock formula in comparison to birth weight. Methods: In this descriptive-analytic study, 96 pregnant women without major fetal anomaly participated. Sonography was preformed 10 days prior to delivery. Biparietal diameter (BPD), femor length (FL) and abdominal circumference (AC) were measured and fetal weight was calculated according to Hadlock Formula. The fetal weight was determined immediately after birth. The difference between these two weights was analysed by t-test and variance analysis. P<0.05 was considered significant. Results: In these 96 pregnant women the range of birth weights was 2000-4100 grams. The mean difference between sonographic EFW and birth weight was 237.8 grams. In 26%, it was less than 100 grams and in 66.7%, less than 300 grams. There were no significant difference between weight groups of 3500 grams. Conclusion: Sonographic EFW has acceptable value in clinical decision-making.