New Gestational Age Parameter - Transverse Diameter of Heart - TDH

Introduction: Fetal growth assessment, for induction and timing of repeat caesarean, relies on accurate gestational age. Various ultrasonography fetal biometry has been used to assess gestational age in practice. This information is invaluable because most obstetrical management decisions are strongly influenced by consideration of fetal development, which closely correlates with fetal age. Aim: To evaluate the accuracy of fetal Transverse Diameter of Heart (TDH) measured by real time ultrasound to predict the gestational age during second & Third diameter and to correlate with FL. BPD, AC, HC to assess variation. Materials & Methods: Prospective Study was carried out at Saveetha Medical College. Total 150 cases attending antenatal clinic in first, second & third trimesters were considered. Routine measurements of FL, BPD, HC, AC along with TDH taken. TDH is taken in mm at closed AV valve junction, outer to outer points in four chamber view of heart. Results: Out of 150 cases 64 were in second trimester, 86 in third trimester. 102 patients had confirmed first trimester gestational age TDH in second & third trimester is more closed to actual gestational age than average gestational calculated by other parameters. The TDH was calculated and found that the variance in the second half (from 28 weeks onwards) was stated to be very less as shown in the tabulated value as variance of 0.01376 as against first half of 0.0393. The population confidence interval was 0.95%. From Predicted value of TDH & confidence interval, we suggest that when compared to other parameters like BPD Bipariteal diameter, HC head circumference FL femur length. AC abdominal circumference - TDH Transverse diameter of heart dimensions are equivalent to actual gestational age from 28 week on wards. Conclusion: TDH can be a useful parameter when LMP is not known. It can be used as additional parameter when ever needed.