What are birth defects? A birth defect is an abnormality caused by a morphological structure, physiological function abnormality or metabolic defect that occurs in the mother’s womb before the child is born. The most common fetal anomalies include: trisomy 21, congenital heart disease, neural tube defects, cleft lip and palate, polydactyly, hydrocephalus, etc. Physiological function and metabolic defects often lead to congenital mental retardation, deafness, mute and other abnormalities. Why do birth defects occur? The causes of birth defects are complex, and there are two main aspects: first, genetic factors, mainly referring to birth defects caused by genetic mutations or chromosomal aberrations, which can be divided into single gene defects, chromosomal abnormalities, and polygenic defects. The second is the environmental factors, including nutrition, disease, infection, medication and exposure to harmful substances. Such as embryonic period (the first 3 months of pregnancy) by a variety of infections or exposure to radiation, chemical substances, drugs, as well as maternal illness during pregnancy, or prolonged work in high temperature and high heat environment. According to data, birth defects caused by genetic factors alone account for 10-25% of birth defects. In many cases, the occurrence of defective children is triggered by environmental factors or is the result of a combination of genetic and environmental factors. According to the results of current studies, the known preventable birth defects can be divided into three categories according to their causes: the first category is micronutrient deficiencies during pregnancy, mainly referring to iodine deficiency and folic acid deficiency, which causes endemic cretinism, and folic acid deficiency, which causes neural tube malformations. The second category is teratogenic factors, the important ones are pregnancy infections, many viral infections in the first 3 months of pregnancy to the first 3 months of pregnancy can lead to ovarian aberrations and fetal malformations, the earlier they occur the more damage to the fetus. The third category is genetic factors, polygenic defects such as congenital heart disease, neural tube abnormalities and cleft lip and palate. What should I do if I have a birth defect? Birth defects focus on prevention, the national focus on the promotion of birth defects three-tier prevention measures can prevent the birth of most defective children or reduce the symptoms. Primary prevention: premarital medical examination and preconception care. This includes pre-marital counseling to find out if there are any diseases that affect the health of the next generation and what preventive measures are needed for both unmarried parties. Before pregnancy, women should choose the best age for childbirth, prevent infections, stop smoking and drinking, avoid exposure to radiation and toxic and harmful substances, avoid exposure to high temperatures, etc., and take folic acid and vaccinations as needed. Marriage between close relatives is prohibited. Secondary prevention: prenatal screening and prenatal diagnosis. Prenatal screening includes Down’s syndrome screening, ultrasound screening, thalassemia screening, thyroid function and diabetes screening, as well as pregnancy health guidance and supervision. Down’s syndrome screening is recommended for 11-13+6 weeks of pregnancy and 15-20+6 weeks of pregnancy, with an accuracy rate of 80% and above. Ultrasound examination at 12-14 weeks of pregnancy, 20-22 weeks of pregnancy and 32 weeks of pregnancy can rule out 80% of fetuses with or without structural malformations. If fetal abnormalities or maternal high-risk factors are found and prenatal diagnosis is needed, it is recommended to perform chorionic villus aspiration at 11-13+6 weeks of pregnancy, amniocentesis at 18-24 weeks of pregnancy, and umbilical vein aspiration after 24 weeks of pregnancy to extract fetal cells for prenatal diagnosis such as chromosomal and genetic diagnosis clinical medical diagnosis, in order to detect and diagnose early and take early measures to prevent The birth of defective babies. Tertiary prevention: newborn screening. The main focus is to carry out screening diagnosis and treatment of congenital hypothyroidism, phenylketonuria, congenital hearing impairment and other diseases, to diagnose defective children early and choose the best time for surgical correction in order to reduce the burden of defective children on families. Birth defect prevention focuses on primary and secondary prevention, i.e. premarital, preconception and pregnancy intervention.