To assess the value of echocardiography in the diagnosis of isolated fetal pulmonary valvular stenosis (PVS).

From January 2019 to December 2022, 35 fetuses diagnosed with PVS by prenatal echocardiography at the Department of Ultrasound of Tianjin Central Obstetrics and Gynecology Hospital and the Department of Ultrasound of Southern District of Chengde Medical College were retrospectively analyzed. Fetal echocardiography was performed to obtain four chamber sections, left ventricular and right ventricular outflow tract sections, and three vessel sections. The transverse diameter of each heart cavity was measured, and the opening and closing of the atrioventricular valve and regurgitation were observed. All fetuses were examined by echocardiography within 24 h after delivery to measure pulmonary artery velocity and pulmonary artery cross-valve pressure difference and evaluate the degree of pulmonary artery stenosis. The results of prenatal and postnatal echocardiography were analyzed, and Pearson correlation was used to analyze the correlation between prenatal PVS grouping (forward group and reverse group) and postpartum PVS grading (mild, moderate, and severe).

Of the 35 fetuses with PVS included, 8 underwent induced labor and 27 were born. There were 15 cases in the forward prenatal ductus arteriae (DA) group and 20 cases in the reverse prenatal DA group, and there were statistically significant differences in pulmonary artery velocity, dilation of the pulmonary artery after stenosis, and tricuspid regurgitation between the two groups (P<0.05). There was no significant difference in pulmonary artery diameter, left and right pulmonary artery diameter, pulmonary valve opening, and right ventricular diameter/left ventricular diameter ratio (P>0.05). All 27 cases of PVS in neonatal period were confirmed by echocardiography, of which 15 were mild, 8 were moderate, and 4 were severe. There was a correlation between different groups of prenatal PVS and different grades of postpartum PVS (Pearson correlation coefficient=0.58, P<0.05). Mild PVS (12/14 85.71%) was found mainly in the positive prenatal group, while moderate and severe PVS (10/13 76.92%) was found predominantly in the reverse group.

Pulmonary artery velocity is fast and tricuspid valve regurgitation is severe in fetuses with isolated PVS. The possibility of moderate or higher PVS is high after DA reverse perfusion. Dilation after stenosis is an important indirect sign of fetal PVS. Fetal PVS alone can be diagnosed before birth, and echocardiography is an important means to diagnose isolated fetal PVS and estimate its postpartum grade.