Johnson’s formula to compare fetal weight with actual birth weight

Abstract

Introduction: Accurate fetal weight assessment is a problem which is associated where resources are subject to availability. Both low and high birth weight is connected with augmented prospect of complications of new born during labour and purperium. Fetal weight assessment can reduce the risk of complications that are challenging in maternal and neonatal of Symphysio-fundal height measurement by adopting Johnson’s Formula. For the fetal weight estimation a method that has now come to be prevalent. By adopting Johnson’s formula along with its comparison to the actual birth weight. The present study thus aimed to determine fetal weight accuracy. Materials and Methods: Present study of prospective analytical was accepted to in the Obstetrics and Gynaecology Department of a tertiary care hospital in Pune. Study included a total of 500 pregnant women attending the OPD with full term pregnancy till onset of labour, fulfilling the inclusion criteria. Adopting Johnson’s formula birth weight estimation has been done along with the results were correlated with definite birth weight. Using SPSS ver. 21.0 the analysis of Data had been performed. Results: As per the prediction of Mean birth weight by clinical (Johnson’s formulae) and actual birth weight was 3.13 Kg and 2.89 Kg correspondingly. Johnson’s formulae’s co-relates well with actual birth weight (r-0.86; 95% CI: 0.84-0.88), though prediction of fetal weight was slightly on a higher side. In 60.8% cases the difference was within range of 10% and in 84.8% the difference was less than 15%. The mean difference in estimation was highest in babies those are in low birth weight i.e. <2.5 Kg. Conclusion: Our observation indicates that as a diagnostic tool there is visibly a role for clinical birthweight estimation, in a pregnancy term suggesting that, to manage labour as well as delivery clinical estimation is sufficient.