Comparison of the estimated fetal weight measurements by 2 and 3 dimensional ultrasound at term pregnant women

Objective

To analyze the 2-dimensional and 3-dimensional ultrasound estimation of fetal weight in terms of measurements and the accuracy of the formulas used in the comparison of these measurements

Methods 

165 pregnant women who were delivered at Zekai Tahir Burak Women's Health Education and Research Hospital were included in the study. Informed consent was obtained from participants and the study was approved by the Hospital Ethics Committee. Pregnant women who participated in the study were selected according to the following criteria: being at 37-42 weeks of gestation without any pregnancy complications and delivering within 48 hours of ultrasonographic measurements. 2D and 3D ultrasound measurements were performed by the same physician(H.E.). Estimated fetal weights(EFW) were calculated from registered biometric values of the 2D and 3D images of thigh processed EFW programme and Viewpoint PIA 's were calculated. The most widely used 2D measurements EFW Hadlock I (BPD, AC, FL), Hadlock II (BPD, HC,AC, FL), Shepard (BPD, AC) formulas were used to estimate fetal weight. In terms of 3D measurements, EFW were calculated from the formulas of Lee I (TVol), Lee II (TVol, AC), Lee III (TVol, AC, BPD). Statistical analysis of the study was carried out by SPSS 17 (SPSS, Chicago,IL USA). The difference between the EFW from the different formulas and the birthweight at delivery was obtained and analyzed by using paired sample t-test.

Results

Estimated fetal weights for all formulas significantly correlated with birthweights. In comparison of the infant birth weights and estimated fetal weights for each formula, no statistically significant difference was detected for Lee I, Hadlock II, Hadlock I; whereas there was significant difference for Lee II, Lee III, Shephard. P values of Lee I, Hadlock II and Hadlock I were 0667,0.526, 0.016) respectively.

Conclusion

Ultrasonographic estimation of fetal weight has been widely used in labor wards. Estimation of fetal weight by 3-D ultrasound including soft tissue volume appears to be more accurate in Lee I formula than the other 2 and 3 D formulas in low risk term pregnant women delivered within 48 hours of measurement.

Keywords

2D ultrasound, 3D ultrasound, fetal weight