Abstract

Introduction: The estimation of fetal weight is of paramount importance in the management of labor and delivery. The study was conducted to find usefulness of clinical estimation of fetal weight as it is useful for developing countries where ultrasonography facilities are unavailable in many areas.

Aim: The study aimed at determining accuracy of fetal weight estimation clinically by Johnson’s formula and ultrasonographical by Hadlock’s method.

Material & Methods: A descriptive study in the department of obstetrics and gynecology at a tertiary care hospital in western India was conducted between July 2017-June 2018 on pregnant patients with 37 to 40 weeks gestation after applying inclusion and exclusion criteria.

Results: The study group consists of 260 subjects from urban, rural settings and different socio-economic classes. There was positive correlation between actual birth weight and Johnson’s formula weight (R=0.533, P= 0.000) as well as between actual birth weight and estimated weight by ultrasonography (R= 0.736, P= 0.000). The differences in the estimation of birth weights between the two methods were statistically significant with P value = 0.004. The maximum error in fetal weight measurement was observed with Johnson’s formula (1420gms) as compared to ultrasonography (900gms). The range of percentage error was less than 5% in ultrasound method compared to 31.9% with Johnson’s method therefore ultrasound method has less error compared to Johnson’s method (statistically significant, p value 0.036).

Conclusion: The study highlighted that there was no significant difference between the mean weight obtained through clinical and ultrasound assessments and actual birth weight. Both clinical (Johnson’s formula) and ultrasound methods of foetal weight estimation showed positive correlation with actual birth weight of the foetus after delivery. The clinical method should remain a valuable alternative where ultrasound is unavailable as it also has strong correlation with the actual birth weight.

Keywords: Fetal weight estimation: Johnson’s formula; Hadlock’s method