Lalmohan Nayak1, Kumudini Pradhan2, Kruthika M. L3
Foetal weight is one of the greatest factor determining the survival of the foetus. Estimation of foetal weight predelivery helps to decide the mode of delivery and anticipate problems during labour.
Aim of the study is to assess the foetal weight in term pregnancies by various methods, i.e. abdominal girth x symphysiofundal height (Insler’s Formula), Johnson’s formula and Hadlock’s formula using USG to study the accuracy of these methods and to correlate these methods of estimation of foetal weight with actual birth weight of the baby after delivery.
MATERIALS AND METHODS
200 cases having term pregnancies were selected from antenatal clinics and maternity wards in whom delivery was anticipated within one week of foetal weight estimation. Foetal weight estimation was done clinically by two methods, i.e. AG x SFH, Johnson’s formula and by ultrasound using Hadlock’s formula. Results were compared to the actual weight of the babies after delivery with respect to mean birth weight±SD and average error in estimating foetal weight and prediction of birth weight within 10% of actual birth weight. Statistical analysis was done using Student’s t-test, Pearson’s correlation.
The mean birth weight by symphysiofundal height * abdominal girth±SD was 2967.79±348.52 whereas mean of actual birth weight±SD was 2903±460.02. The p value calculated to be 0.118, which is statistically not significant. Average error in estimating foetal weight was 189.2 g by Hadlock’s formula and 304.2 g by AG x SFH method. The difference is not statistically significant. Prediction of birth weight within 10% of actual birth weight was in 63.5% of cases by AG x SFH formula, 81% by Hadlock’s formula and 49% by Johnson’s formula.
AG x SFH (Insler’s formula) has better predictable results is foetal weight estimation as difference between it and actual birth weight is not statistically significant making SFH * AG method more accurate for estimation of foetal weight if compared to actual birth weight. So, it can be of great value in a developing country like ours where ultrasound is not available at many healthcare delivery systems.