Comparative study of fetal weight estimation by various methods at term and its correlation with the actual birth weight

Abstract

INTRODUCTION: Modern obstetrics aims to achieve the best quality of life for both mother and her unborn child. Birth weight is an important predictor of neonatal outcome, and its prenatal estimation plays a significant role in the comprehensive evaluation and management of high- risk pregnancies. This study aims to estimate fetal weight using different clinical methods and ultrasonography and compare these methods with the actual birth weight.

METHODS: A prospective cross-sectional comparative study of 200 full-term pregnant women admitted to the Northern Railway Central Hospital, New Delhi, between June 2014 and June 2015 was conducted. Patients in whom delivery was anticipated and completed within 1 week were included. Fetal weights were estimated clinically using Insler’s and Johnson’s formula and ultrasound using Hadlock’s formula. Estimates were then compared with actual birth weight. RESULTS: Both the clinical methods showed underestimation of fetal weight, while ultrasound estimation of fetal weight showed overestimation. Clinical methods had a lower average error in fetal weight estimation than ultrasonography methods. Reliability statistics showed a better prediction of fetal weight if all three methods were used in conjunction.

CONCLUSION: Clinical methods were found to be better than the ultrasonography method for fetal weight estimation. Clinical methods are easy and cost-effective for the patients, so all relevant health workers should be taught how to undertake this skill competently. However, all the methods must be used in conjunction.