RESUMO
Premature constriction or closure of fetal ductus arteriosus usually occurs during late pregnancy, causing cardiac ventricular size disproportion (right and left heart asymmetry), which are usually clues for the diagnosis. We reported a case of a fetus with an enlarged right heart, reduced wall motion of the right ventricle, and severe tricuspid regurgitation identified by echocardiography at 37 +2 gestational weeks. Furthermore, the fetal ductus arteriosus was unclear on two-dimensional fetal echocardiography, and high-velocity flow was detected at the site by pulsed-wave Doppler, suggesting a significant premature constriction of fetal ductus arteriosus. The elective cesarean section was performed after the examination day. Three months postpartum examination showed no obvious abnormalities in the heart of the newborn.