Comparison of Fetal Weight Estimation with Clinical, Ultrasonographic Methods, and Combined Formula of Ultrasonography and Maternal Weight

Document Type : Original Article


1 Associate Professor, Department of Obstetrics and Gynecology, Infertility and Reproductive Health Research Center, School of Medicine, Babol University of Medical Sciences, Babol, Iran.

2 Medical Student, School of Medicine, Babol University of Medical Sciences, Babol, Iran.

3 General Practitioner, Non-Communicable Pediatric Diseases Research Center, School of Medicine, Babol University of Medical Sciences, Babol, Iran.


Introduction: Accurate fetal weight estimation is clinically important because of known complications of the wrong estimation. Since there are different ideas about fetal weight estimation methods, this study was designed to compare fetal weight estimation with clinical and ultrasonographic methods, and combined formula of ultrasonography and maternal weight.
Methods: This descriptive-analytic study was conducted on 160 singleton pregnant women with gestational age of 37-41 weeks in Ayatollah Rohani hospital of Babol, Iran during 2010-2011. Fetal weight was estimated clinically by Leopold's maneuvers, ultrasonographic and a combination of ultrasonography and maternal weight (Hart formula). Birth weight of neonates was measured accurately during less than three days after estimating fetal weight and child birth. Estimation error and percentage of estimates within 10% of actual birth weight were measured and analyzed by SPSS software version 18, t-test and Pearson correlation coefficient tests. P value less than 0.05 was considered significant.
Results: Mean of actual birth weight was 3422.56±442.24 grams. Mean of fetal weight estimation with clinical, ultrasonographic, and Hart formula methods were respectively 3395±336.28, 3367.57±388.11, and 3178.89±428.71 grams. Clinical estimation had fewer errors in weight estimation. The percentage of estimates within 10% of actual birth weight was 74.4% in clinical, 73.1% in ultrasonographic estimation by Hadlock Ш formula, and 3.46% in Hart formula methods. The difference between clinical estimation by Leopold's maneuvers and ultrasonographic method was not statistically significant (p=0.79). The estimate within 10% of actual birth weight with Hart formula was significantly different with two other methods (p=0.001).
Conclusion: Both clinical estimation by Leopold's maneuvers and ultrasound assessment (Hadlock III) of fetal weight are associated with actual birth weight but hart formula assessment has less accuracy in compared of two methods.


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