[Study of endocardiac and extracardiac haemodynamics changes in fetus with increased nuchal translucency thickness]

To explore the characteristics of endocardiac and extracardiac haemodynamics parameters in fetus with thickened nuchal translucency (NT) and analyze the relationship between hemodynamic changes and fetal prognosis.

The fetal appearance was observed during the first trimester. And the thickness of NT or soft tissue of neck was quantified. The endocardiac and extracardiac haemodynamic parameters were measured by ultrasound Doppler. The parameters were compared between fetus with thickened NT and normal fetus. Echocardiography was performed individually in both 2nd trimester and newborn stage.

Eight cases with greater NT thickness were found. Four cases terminated pregnancy during the first or second trimester: one was diagnosed as persistent arterial trunk during a 13-week gestation, one with congenital cystic adenomatoid malformation during second trimester. Both were confirmed by autopsy; one with pleural fluid and ascites while another aborted at the expectant mother's will. Four cases were delivered full-term. Among them, one had congenital anal atresia while the other 3 cases were normal. Endocardiac haemodynamic parameters were normal in all cases with thickened NT and no heart malformation. Higher pulsatility index (PI), resistive index (RI) and ratio of velocity of systole and diastole (S/D) in venous duct were observed in 5 cases. The endocardiac and extracardiac haemodynamics parameters of the cases with thickened NT and complicated with heart malformation were different from normal cases.

Greater NT thickness is closely correlated with chromosomal abnormalities, congenital cardic defects, other structure abnormalities and a poor prognosis. Ultrasound Doppler can evaluate the fetal heart functions accurately. If abnormal endocardiac and extracardiac parameters are found in fetus with thickened NT, the existence of heart malformation should be considered. When abnormal extracardiac Doppler waveshape or greater blood flow resistance is found with normal endocardiac parameters, prognostic follow-ups should be conducted with chromosomal examinations.