Accuracy Of Various Ultrasonographic Formulae In Predicting Fetal Weight – A One Year Prospective Longitudinal Study

Abstract

Objective To assess the accuracy of 4 ultrasonographic formulae (Shepard, Hadlock II, Hadlock III and Hadlock IV) in predicting fetal weight. Methodology: This one year prospective longitudinal study was conducted at the teaching hospital attached to KLE University’s Jawaharlal Nehru Medical College, Belagavi during the period of January 2016- December 2017. A total of 114 pregnant women admitted to the labour room and antenatal ward were enrolled in the study. Ultrasound examination was done by three specifically identified obstetricians and fetal biometry was measured. EFW with the help of fetal biometric parameters were calculated separately for every patient using all the 4 equations. Actual birth weight (ABW) of all the newborns delivered was measured in kilograms. Result : Karl Pearson’s correlation co-efficient was highest with Hadlock IV (r =0.9152).For detection of newborn <2.5 kg, Shepard’s formula had the highest sensitivity i.e 91.67%, Hadlock II and Hadlock IV had the highest specificity (95.56%). For detection of newborn >3.5 kg, all the four formulae had the same sensitivity (80.00%) and specificity was highest with Shepard’s formula(99.08%) Conclusion: All the formulae have adequate accuracy for estimating fetal weight, Hadlock IV has the best accuracy. Sensitivity and specificity of each EFW formula changed with different weight ranges.