Fetal Echocardiography:
Measurements were performed using the Voluson S10 (GE Medical Systems) ultrasonography device with a 3.5 MHz convex transducer (6C1-PVT-375BT) transabdominal probe by the same experienced maternal fetal medicine specialist. To avoid variations, the three clearest waveforms with the normal range of fetal heart rate were obtained and averaged. The two-dimensional (2D) and M-mode imaging of apical four-chamber and parasternal long axis view at the end-diastol was used for fetal heart rate (FHR), left ventricle posterior wall thickness (LVPWd), septum thickness (IVSd), right and left ventricular end-diastolic dimensions (RVEDD, LVEDD), mitral and tricuspid annular plane systolic excursion (MAPSE, TAPSE) measurements. Mitral and tricuspid peak early ventricular filling (E) wave velocity, maximum active atrial filling (A) wave velocity (cm/s) E wave deceleration time (msn) of mitral and tricuspid valve (MEDT, TEDT), max peak velocity of aortic (AV) and pulmonary valves (PV) obtained from pulsed wave doppler imaging (PW). Tissue doppler imaging (TDI) measurements were performed on the basal septum and on the lateral walls of right and left ventricle. TDI parameters the maximal systolic myocardial velocity (Sm), early and late diastolic myocardial velocities (Em, Am waves), isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT), ejection time (ET) of the walls are measured. Myocardial performance index (MPI, Tei index) was calculated according to the formula (IVCT+IVRT)/ET).