Abstract Objective To explore clinical significance of premature constriction of the fetal ductus arteriosus (DA) detected by echocardiography in middle and terminal gestation. Methods Premature constriction of the fetal DA in Thirty-seven fetuses was diagnosed by prenatal echocardiography. The echocardiography, clinical presentation and prognosis were reviewed and analyzed．Results Comparison with normal fetuses with matched gestational ages, narrowing of the inner diameter of the DA was significant, increasing of the diameter of the right atrium (RA), right ventricle (RV) and pulmonary artery (PA) were significant (P﹤0.05), and with moderate to severe tricuspid regurgitation, turbulent flow within the DA with peak systolic velocity increased. Among 8 patients who underwent emergency cesarean section, DA closed within 24h after birth in 4 cases, 1 infant died on the 12th day after birth, 1 case with fetal edema was cured. In addition, there were no obvious abnormalities in 19 cases. 1 case chose termination of pregnancy induced abortion. 11 cases were loss to follow-up. Conclusion Moderate to severe tricuspid regurgitation and right heart load increased were present in fetuses with premature constriction of the DA during terminal gestation. Active monitoring with prenatal echocardiography plays an important role in evaluating fetal intrauterine conditions and prognosis.