Critical evaluation of various methods of estimating foetal weight by ultrasound

Abstract

Summary: This prospective study was conducted in a peripheral hospital of Kasturba Medical College; Manipal to know which sonographic method of estimation of foetal weight reliably predicts the birth weight. 100 patients were scanned thoroughly within 48 hours of delivery. Seven different models of ultrasonic weight estimation were analysed critically. It was found that the method of Hadlock2, predicted the birth weight more accurately than others. The average deviation from the actual birth weight (226gms), the percentile values of absolute error of difference were least with this method and it predicted maximum number of cases within 10% of actual birth weight (85%). Significant differences were observed between the predicted and actual birth weight in all other methods (p<0.01). It was concluded that this method is superior predictor of birth weight compared to other six and is a method of choice to estimate the birth weight in term pregnancies where the measurements of foetal head is inaccurate either because of engagement or moulding, as it incorporates only FL and AC measurements which is not affected by these changes.