Moderate mitral regurgitation may cause symptoms of cardiac insufficiency such as dyspnea, shortness of breath, and chest tightness in the fetus after birth. Fetal mitral regurgitation is a congenital heart disease that may or may not cause heart insufficiency in the fetus after birth with no obvious symptoms. Whether mitral regurgitation has a major effect on the fetus depends mainly on the degree of mitral regurgitation. If the mitral regurgitation is only mild, it usually does not affect the fetus too significantly. If the mitral regurgitation is moderate to severe, the fetus may have obvious symptoms such as dyspnea, shortness of breath and chest tightness after birth. Regular ultrasound monitoring of the fetal heart can be performed during the examination to clarify the current condition of mitral regurgitation, and if necessary, surgical treatment will be required in the hospital after birth.