Estimation of Fetal Weight at Term by Clinical Method Using Symphysio Fundal Height and Abdominal Girth and Ultrasound Using Hadlock Formula and Its Correlation with Actual Birth Weight

Abstract

In prenatal care, labor management and preparation, particularly when deciding on the mode of delivery, the accuracy of fetal weight predictions is crucial. At both extremes of birth weight, perinatal complications are higher, so it is also necessary to develop conceptual strategies to reduce the rate of unwanted pregnancy outcomes. The purpose of this study was to estimate the fetal weight during term pregnancy using clinical and ultrasonic methods, as well as to correlate the actual birth weight with the estimated weight. Materials and methods: A prospective observational study of all term pregnant women who came for antenatal checkup and patients admitted to the obstetric ward fulfilling the inclusion criteria. The patients were subjected to clinical evaluation and investigations, and data was collected in a predesigned pro forma. All the measurements were routinely documented in the antenatal visit of pregnancy, and the estimated weight was calculated by using the formula abdominal girth (AG) × symphysio fundal height (SFH) and Hadlock method and both were compared with the weight of the fetus after delivery. Results: A total of 500 pregnant women with singleton pregnancies were studied. The average actual birth weight was 2758.19 ± 341.25. The mean weight estimated by AG × SFH was 2862.67 ± 327.37, and that by the Hadlock method was 2902.11 ± 336.35. The p-value of the estimated fetal weight (EFW) by AG × SFH was 0.699, whereas for the Hadlock method, it was 0.669. The average error was 104.50 gm with AG × SFH and 143.9 gm with the Hadlock method. The mean percentage error was 3.8% in AG × SFH and 5.1% by the Hadlock method. The standard deviation (SD) was found to be the smallest with AG × SFH (197.85), followed by ultrasound (USG) (219.61). Correlation analysis showed a significant positive relationship between the weight of the fetus at birth and the estimated birth weight for both methods. Conclusion: From the present study, we conclude that the estimation of fetal weight at term by a clinical method is as accurate as the USG estimation of fetal weight. It can be routinely used at term gestation. It is of more practical use at peripheries where USG machines or trained personnel for doing USG are not available.