According to statistics, the incidence rate of birth defects in China is 5.6%. The total number of birth defects is about 900 thousand per year, with 250 thousand cases of birth defects visible at birth. The most common major birth defects include congenital heart disease, cleft lip and palate, hydrocephalus, neural tube defects and mental retardation. Birth defects seriously harm the quality of our country’s birth population and bring huge burden to the society and family. The rapid development of prenatal screening and prenatal diagnosis technology provides the possibility of screening genetic diseases and congenital malformations, which is of great significance to reduce the birth rate of sick fetuses and improve the quality of birth population. Prenatal screening and prenatal diagnosis are two key points to prevent birth defects.
birth defect refers to the abnormal development in the mother’s uterus before birth, which can be structural abnormality, physiological function or metabolic abnormality. Severe birth defects can lead to miscarriage, stillbirth, stillbirth and infant death, or lead to children’s illness and long-term disability.
most birth defects are mainly caused by genetic factors and environmental factors. The high risk factors of birth defects include: the age of expectant mother, family history of birth defects related diseases, having given birth to children with birth defects, exposure to toxic and harmful substances before and during pregnancy. At present, we advocate the scope of birth defects screening is “the whole population”, that is, all pregnant mothers. Because the cause of birth defects is still not very clear, in addition to high-risk groups, any normal pregnant women may also give birth to children with birth defects.
prenatal screening includes common autosomal aneuploidy screening and prenatal ultrasound screening. Blood biochemical screening in the second trimester is usually carried out at 15-20 weeks + 6 days of pregnancy. By quantitative determination of some specific biochemical indicators in maternal blood, high-risk groups with trisomy 21, trisomy 18 and open neural tube malformation are screened out for further diagnosis.
fetal free DNA detection in maternal peripheral blood of pregnant women is the application of molecular genetic technology such as high-throughput gene sequencing to detect fetal free DNA fragments in maternal peripheral blood during pregnancy, so as to assess the risk of common fetal chromosomal aneuploidy. It is a prenatal screening technology, which has the characteristics of noninvasive, high sensitivity and high accuracy. However, due to the technical limitations, the target diseases are three common fetal chromosomal aneuploidy abnormalities. This technique is applicable to pregnant women whose risk value of common chromosomal aneuploidy is between high-risk cut-off value and 1 / 1000; those who have contraindications of interventional prenatal diagnosis; those who miss the best time of serological screening but require to assess the risk of trisomy 21, trisomy 18 and trisomy 13 when they are pregnant for more than 20 weeks + 6 days. Screening should be performed between 12 and 22 weeks of gestation.
ultrasound screening has no obvious damage to the mother and fetus. The method is simple, and most of the fetal severe structural malformations can be detected by ultrasound. Therefore, all pregnant women should carry out systematic ultrasound screening in appropriate gestational weeks. The specific screening time was 11 ~ 13 weeks + 6 days and 20 ~ 24 weeks.
prenatal diagnosis includes genetic counseling, ultrasound imaging diagnosis, cytogenetics and molecular genetic diagnosis. Prenatal diagnosis services should be recommended for those at high risk of prenatal screening, those with too much or too little amniotic fluid during pregnancy, those with abnormal fetal development or suspected fetal malformations, pregnant women exposed to substances that may cause fetal congenital defects in the early pregnancy, pregnant women with family history of genetic diseases or poor fertility history, and pregnant women over 35 years of age should be advised to accept prenatal diagnosis services.
amniocentesis, chorionic biopsy, umbilical cord puncture, fetal endoscopy, etc., which are highly concerned by the public, are all interventional methods for prenatal diagnosis, so as to obtain fetal cells or tissues for genetic analysis, which can further clarify the abnormalities at chromosome and gene levels. Different gestational weeks, different diseases to take the corresponding method. Amniocentesis is the most commonly used method, usually between 18 weeks and 22 weeks of pregnancy. Amniocentesis is also relatively safe. The incidence of abortion and other adverse consequences within one week of puncture is 1 ‰ ~ 2 ‰. Therefore, high-risk pregnant mothers must follow the doctor’s advice to complete prenatal diagnosis, timely discover serious birth defects, and prevent birth defects.
the implementation of primary and secondary prevention measures to prevent birth defects before marriage, pregnancy and pregnancy can effectively prevent at least 65% of serious birth defects and play a key role in the prevention of birth defects.
every parent hopes that their children will be smart and healthy, but affected by many factors, even though they have passed the two important barriers to prevent birth defects: pre pregnancy health care and prenatal examination, there will still be a certain number of babies with congenital diseases.
for example, prenatal ultrasound screening is mainly to detect whether there are serious structural abnormalities or abnormalities in the fetus. Due to the influence of various factors, prenatal ultrasound screening and diagnosis can not find and diagnose all fetal malformations, the diagnostic rate of different types of fetal malformations is not the same, even if the best conditions of medical institutions examination rate and diagnostic rate is less than 100%. Affected by many factors, such as fetal bone sound shadow, fetal movement, amniotic fluid volume, ultrasonic instrument and operator’s technical level, obvious malformations after birth, such as cleft lip and palate, hand and foot deformity, eye and ear abnormalities, may also be difficult to show in intrauterine ultrasound examination, and missed diagnosis is difficult to avoid.
in addition, some fetal abnormalities may be affected by external factors during or after fetal development, such as long bone dysplasia, renal abnormalities, cardiac abnormalities, etc. Some fetal abnormalities can be diagnosed only after continuous dynamic observation.
therefore, after the baby is born, it is necessary to find out the children with birth defects, especially those with abnormal functions, such as deafness and congenital metabolic diseases, through neonatal disease screening and children’s systematic health care, so as to make them get early diagnosis and timely treatment, avoid or reduce the occurrence of disability, and improve the quality of life of children.
parents should actively cooperate with doctors in neonatal disease screening, and timely query and retain the screening results. If you receive the reexamination notice, be sure to return to the doctor on time and treat the abnormality in time. Babies who pass the neonatal screening smoothly still need to have regular physical examination according to the requirements. If the growth and development deviation is found, they should be transferred to the designated institution for further diagnosis and treatment under the guidance of primary doctors. HEALTHY LIFE