I. Why do we need fetal echocardiography
The incidence of congenital cardiovascular malformations is 8 per 1,000-1%, and the incidence has ranked first among birth defects, with an estimated 150,000-220,000 new births each year in China. When intrauterine deaths, terminations and stillbirths are included, the estimated prevalence of prenatal congenital cardiovascular malformations is as high as 3-4%. Approximately 50% of congenital cardiovascular malformations are easily corrected by surgical or interventional treatment, while 50% are complex and severe malformations that are difficult to treat satisfactorily with current cardiac surgery or cardiac medical interventions. Therefore, the accurate diagnosis of complex, severe and fatal cardiovascular malformations by fetal echocardiography in the prenatal period is an important task for both maternal-fetal medicine and ultrasound imaging.
Fetal echocardiography is the latest development of echocardiographic technology, and like other ultrasound imaging techniques, it is obviously limited by the experience of the operator, requiring physicians who perform fetal echocardiography and diagnosis not only to master the knowledge and techniques of conventional ultrasound, but also to understand the relevant knowledge in the fields of maternal-fetal medicine, genetics, neonatal medicine, pediatric surgery, pediatric cardiology, pediatric cardiac surgery and other specialties They should also keep in touch with relevant experts in the above fields to get their help and advice.
II. Indications for fetal echocardiography.
(a) Maternal factors
(1) Advanced maternal age > 35 years
2. Mother with congenital heart disease
3, previous history of abnormal pregnancy, such as fetal death, miscarriage, excessive amniotic fluid or too little amniotic fluid, etc.
4, early pregnancy medication, such as lithium oxide, dalentin, etc.; exposure to teratogenic substances during pregnancy, such as radiation, etc.
5, various types of diabetes, connective tissue disease, infectious diseases (such as TORCH infection in early pregnancy)
6.Anti-Ro or anti-La antibody positivity
(2) Fetal factors
1. Cardiac abnormalities suggested by conventional ultrasound examination, which need to be clearly diagnosed
2.Fetal cardiac arrhythmia
3.Organ malformation other than the heart
4.Chromosomal abnormalities
5.Structural abnormalities (hydrocephalus and kidney disorders, etc.)
6.Genetic syndromes and related anomalies
7.Non-immune edema
8.Excessive or excessive amniotic fluid
9, thickening of the posterior nuchal translucency layer
10.Twin pregnancy (twin fetus transfusion syndrome and heartless twin malformation)
12, exposure to teratogenic factors
(iii) Family factors
1.Mendelian syndrome
2.Nodular sclerosis
3.Both parents have congenital heart disease
4.History of fetus with congenital heart disease or pregnancy of the child with congenital heart disease
Because of the technical difficulty of fetal echocardiography, most of the prenatal diagnostic centers at home and abroad in recent years have been limited to performing fetal echocardiography in the middle of pregnancy for fetuses with high-risk factors (recent domestic and foreign literature reports that 50%-89% of fetuses with congenital heart disease do not have high-risk factors), therefore, fetal echocardiography for all fetuses is the most important means to improve the prenatal diagnosis rate of congenital heart disease.
The best time for fetal echocardiography
A systematic routine color Doppler ultrasound must be performed at mid-term pregnancy, including assessment of fetal position, size, amniotic fluid volume, placental position and development of all fetal systems. Fetal cardiovascular examination includes basic cardiac views, blood flow observation and measurement to rule out serious congenital anomalies. The most suitable period for fetal echocardiography is from 20 to 24 weeks of gestation, but in late pregnancy, due to the decrease of amniotic fluid and the restriction of fetal movement, the examination may be difficult.