Mild tricuspid regurgitation in the fourth dimension is usually not Down’s syndrome. Tricuspid regurgitation is a developmental problem of the heart, and Down syndrome most commonly presents clinically with developmental abnormalities as well as mental retardation and other symptoms. Tricuspid regurgitation signifies that some of the blood ejected from the right ventricle into the pulmonary artery is ejected into the right atrium, which can lead to serious complications. However, mild fetal tricuspid regurgitation often resolves on its own and can be checked regularly. Down syndrome, also known as congenital stupidity, is a chromosomal aberration, the most common autosomal disorder in children, and the most common clinical type of mental retardation. Mild tricuspid regurgitation does not cause significant hemodynamic changes, and most of it is a physiologic regurgitation that has no effect on the body. When the fetus is examined in 4D, it has already been screened for Down’s syndrome or non-invasive DNA to check for the risk of Down’s syndrome, which can usually be ruled out. If there is a combination of severe cardiac anomalies and structural abnormalities in other parts of the body, prenatal diagnosis can be performed as prescribed by the doctor, and amniocentesis can be performed to find out if the baby is Down’s syndrome. Four-dimensional ultrasound suggests tricuspid regurgitation, it is recommended to carry out fetal heart ultrasound, prenatal diagnosis by a specialist, and take the appropriate examination and follow-up under the guidance of the doctor.