Objectives To establish normative reference ranges of fetal cardiac hemodynamic between 20 and 34 per weeks including: velocity of mitral valve and tricuspid valve, artery valve, important physiological channel of fetal blood flow; and to summary the fetal hemodynamics characteristics; Simple regression analysis was applied to assess possible correlation between Doppler variables and gestational age.
Methods A cross-sectional study was undertaken on singleton pregnancies with normal fetuses and accurate gestational ages. Totally 2573 normal fetus was divided into 15 groups according to the gestation. According to United States Association of echocardiography guidelines and standards for fetal echocardiography, all Doppler variables were stored to statistic the normal reference value range of Doppler variables and analyse the correlation of these Doppler variables and gestation age.
Concluded the normal reference value of the fetal cardiac Doppler variables.
Fetal cardiac hemodynamics characteristics: E and A peak velocities and E/A ratio for both mitral and tricuspid valves, peak velocity of aortic valve and pulmonary valve, velocity of aortic in systolic and diastolic, velocity of ducts artery systolic and diastolic, S wave, D wave and A wave of pulmonary vein increased as gestational age advanced, but without clear statistic significance (P>0.05), S wave, D wave and A wave of vein ducts decreased in gestation 33, 34 weeks, Vs, Vd and Vs/Vd ratio of middle cerebral artery decreased in gestation 33, 34 weeks (P>0.05). S wave, D wave and A wave of Inferior vena cava shows little change throughout pregnancy (P>0.05) .
Simple regression analysis of correlation between Doppler variables and gestational age, we found that all Doppler variables have no correlation with gestational age.
Conclusions Fetal echocardiography technology can accurately assess fetal cardiac blood flow dynamics; the establishment normal reference value of cardiac hemodynamic could provide guidance to fetal echocardiography examination, all Doppler variables have no correlation with gestational age.