A Comparative Study of Clinical and Sonographic Fetal Weight Estimation at Term with the Actual Birth Weight
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Abstract
Introduction
Determination of fetal weight is of utmost importance in obstetrics as it helps in monitoring intrauterine growth, detecting high risk pregnancy, labour management and delivery of the baby.
Objective
The aim of our study is to compare the accuracy in estimating fetal weight with ultrasound-based Hadlock's formula, clinically based methods- Insler’s, Johnson's formula and actual birth weight.
Methodology
This prospective comparative study was done in a tertiary care centre between December 2021 and March 2022. 60 consecutive antenatal women were recruited in this study after giving informed consent. Hadlock's formula was used to calculate the estimated fetal weight by ultrasonography and the clinical weight estimation was done by using Johnson’s and Insler’s formula and was compared with actual birth weight.
Results
The mean actual birth weight is 3026.93 ± 372.40 grams, the average birth weight determined by Johnson's formula is 3391.92 ± 306.16 grams and the average birth weight determined by Insler’s formula is 3344.13 ± 589.50 grams. The Hadlock’s Formula as compared to Johnson’s and Insler’s formula, has proven to be a very accurate predictor of the baby's actual birth weight with a sensitivity of 96.55%(96.55%> 79.31%> 65.52%).
Conclusion
Ultrasonography estimation is recommended over clinical estimation method as it yields more accurate fetal weight than other clinical modalities. Also, Johnson’s formula has been reported to be more sensitive than Insler’s formula. Thus, in developing countries where the access to the ultrasound is challenging, estimation of fetal weight close to term can be done by clinical method employing Johnson’s formula.
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References
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