Pregnancy is a long and arduous process for the mother, and the development and growth of the fetus in the mother’s womb is full of unknown possibilities. Because of the difficulty of treating congenital heart disease, it often causes lifelong harm to children and family misfortune, which is a heavy topic, but it is what every mother-to-be has to face. With the continuous progress of medical detection technology, fetal echocardiography is currently the most effective screening means, which not only provides a scientific basis for clinical diagnosis, but also reduces the chance of birth of malformed children. The necessity of fetal heart ultrasonography Fetal heart ultrasonography is unanimously recognized both at home and abroad as the first choice of important imaging method that is non-invasive, accurate, fast and repeatable to detect fetal cardiovascular developmental abnormalities, which can accurately diagnose cardiovascular developmental abnormalities in fetal period and continuously evaluate cardiac function dynamically, and can determine which precardial diseases have the possibility of self-healing, which can be treated radically or palliatively after birth, and which cannot be This is the key to reducing birth defects and improving early treatment after birth. To achieve early and timely diagnosis of congenital heart disease requires not only advanced screening equipment and experienced ultrasonographers, but also the cooperation and attention of pregnant women and their families. Therefore, on the one hand, pregnant mothers should have regular maternity checkups on time, and on the other hand, they should follow the doctor’s advice and make appointments for fetal system ultrasound or special heart examinations. Accuracy of Fetal Heart Ultrasound Current studies show that fetal heart ultrasound is 95% sensitive and more than 85% accurate in diagnosing fetal heart malformations. It can screen for most cardiac developmental anomalies, especially some serious anomalies with poor prognosis, such as cardiac ectasia, single ventricle, single chamber heart, permanent arterial trunk, ventricular dysplasia, dissection or atresia of the great arteries, severe tetralogy of Fallot and valvular atresia. However, it is difficult to detect small ventricular septal defects, atrial septal defects, mild pulmonary artery stenosis, and mild tetralogy of Fallot. Safety of fetal heart ultrasound Prenatal ultrasound is generally considered to be safe and harmless, and there are no studies to confirm that diagnostic prenatal ultrasound has adverse effects on the embryo and fetus. The sonographer follows the “minimum dose” principle when performing a fetal ultrasound, which means that the test is performed with the least amount of ultrasound energy possible, while limiting the duration of a single test. Therefore, pregnant mothers should not be overly concerned about the safety of the test, and when it is necessary to perform a special ultrasound examination of the fetal heart, it should be performed as often as possible to detect or rule out malformations at an early stage and to reduce unnecessary worries. Timing of fetal heart ultrasound examination The primitive heart tube is formed from the 2nd week of normal embryo, and gradually goes through the developmental process of elongation, twisting, rotation and separation until the end of the 8th week of embryo, when the normal heart vascular structure is formed, but the early fetal heart is small, and the cut surface does not show well. 20 weeks~28 weeks is the best period for fetal echocardiography exploration. Which high-risk pregnant women should not ignore this test? 1. Pregnant women with high-risk pregnancy or overdue pregnancy; 2. Pregnant women with a history of infection or medication in the first trimester, especially those who take medication for cold or viral rubella; 3. Pregnant women with a history of long-term exposure to toxins and radiation, such as those engaged in the chemical industry; 4. Pregnant women with blood disorders, endocrinopathies, connective tissue diseases, cardiovascular diseases or genetic diseases; 5. Pregnant women with bad habits such as smoking and drinking alcohol; 6. Pregnant women with intra- and extra-cardiac malformations 6, the pregnant woman has a history of adverse births, a family history of heart disease. Other tests have confirmed or suspected intra- and extra-cardiac malformations or chromosomal abnormalities in the fetus; 7. abnormal intrauterine development, too much or too little amniotic fluid; 8. fetal heart rate is too fast, too slow or rhythmically irregular.