Giving birth to a normal, healthy, and intelligent baby is the common wish of every pregnant mother, every family, and obstetrical medical staff. my country is a country with a high incidence of birth defects, with an incidence rate of 4% to 6%. It is not only the leading cause of neonatal death but also the leading cause of infant morbidity and mortality and an important cause of severe disability in adults. Therefore, efforts to reduce the incidence of birth defects and improve the quality of the birth population are important tasks facing our country.
Birth defects refer to abnormalities in embryonic development due to genetics, environment, or the combined effects of genetics and environment, leading to congenital abnormalities in individual organ structure, functional metabolism, mental behavior, etc. Birth defects include congenital anatomical malformations (appearance and/or visceral malformations) and congenital disorders of physiological function and mental behavior of any part of the fetus. How to screen and diagnose fetal malformations during pregnancy is very important to prevent the birth of children with defects.
Prenatal screening is to screen ordinary pregnant mothers through maternal serology, imaging and other non-invasive methods, and select high-risk pregnant women who may have fetal abnormalities for prenatal diagnosis. Prenatal screening includes prenatal screening for fetal aneuploidy (chromosome testing) and screening for fetal structural abnormalities. Because birth defects are possible at any age, we recommend that all pregnant women undergo prenatal screening.
Prenatal diagnosis refers to the application of various detection methods before the fetus is born to understand whether the fetus has obvious structural abnormalities, whether there are genetic diseases such as chromosomal diseases or genetic diseases, and to provide further intervention for birth defects (including intrauterine fetal treatment and selective termination). Pregnancy) provides evidence.
Amniocentesis is a type of prenatal diagnosis. Because it is an invasive test, pregnant mothers often have some misunderstandings. Let’s look at two real cases first.
Real case 1 Zhang Moumou, 32 years old, had her first child. She had regular prenatal check-ups and was 16 weeks pregnant. She followed the obstetrician’s recommendation for prenatal screening. The result was high-risk. The doctor recommended going to a prenatal diagnosis institution for amniocentesis for prenatal diagnosis. After going to the hospital for consultation, I learned that amniocentesis has certain risks. The pregnant woman and her family were very anxious and finally gave up on amniocentesis. As a result, a boy was born at full term. Trisomy 21 was later confirmed by a chromosome test, and the family regretted it. If amniocentesis was performed on the advice of a doctor, such a tragedy would not have happened.
Real case 2 Li Moumou, 38 years old, first child, regular prenatal check-up, 17 weeks pregnant. Because she is over 35 years old, the doctor recommended direct amniocentesis for prenatal diagnosis. The pregnant woman accepted it, and the amniocentesis result was 21-trisomy. Sign, induce labor.
Like the above two cases, pregnant women and their families must have heard of amniocentesis, but what they are most concerned about and troubled about is the risk of this operation, and they don\’t know whether they should do it. After reading these two real cases, I wonder if pregnant mothers’ views on amniocentesis have changed. Don’t worry, the following will teach you how to correctly understand amniocentesis.
Which pregnant women need prenatal diagnosis?
1 aA 35-year-old pregnant woman. The rate of fetal chromosomal aberrations increases because of the increased chance of chromosome nondisjunction during meiosis in older eggs.
2. High-risk groups identified by prenatal screening.
3. Pregnant women who have given birth to a fetus with chromosomal abnormalities are a high-risk group, because their risk of having another baby with chromosomal abnormalities (such as trisomy 21, trisomy 18, and trisomy 1-3) is 10 times higher than that of normal pregnant women.
4. If one of the couples has a balanced chromosomal translocation, their offspring will have a higher risk of developing chromosomal aberrations.
5. Children who have given birth to anencephaly, hydrocephalus, spina bifida, cleft lip, cleft palate, and congenital heart disease have a higher chance of recurrence in their offspring.
6. For carriers of sex-linked recessive genetic diseases, 1/2 of male fetuses will be affected and 1/2 of female fetuses will be carriers.
7. One spouse has a congenital metabolic disease, or the pregnant woman has given birth to a sick child.
8. Pregnant women who have received large doses of chemical poisons, radiation or severe viral infections in early pregnancy.
9. Pregnant women with a family history of genetic diseases.
10. Pregnant women with a history of repeated unexplained miscarriages, stillbirths, malformations and neonatal deaths.
11. Pregnant women with polyhydramnios and suspected abnormalities in this pregnancy
What is amniotic fluid?
There are many methods of prenatal diagnosis, and amniocentesis is one of them. First, let’s look at what amniotic fluid is. Amniotic fluid is an appendage of the fetus (placenta, fetal membranes, umbilical cord, and amniotic fluid are collectively referred to as fetal appendages). The amniotic membrane in the fetal membrane forms the amniotic cavity, and the fluid in the amniotic cavity is called amniotic fluid. The fertilized egg forms an amniotic cavity on the seventh day of fertilization and begins to produce amniotic fluid. The amniotic fluid volume is 5-10 ml at 8 weeks of pregnancy, 30 ml at 10 weeks of pregnancy, 400 ml at 20 weeks of pregnancy, and reaches a peak of 1000-1000 ml at 36-38 weeks. 1500ml, gradually reduced to about 800ml as the due date approaches. Amniotic fluid is 98% to 99% water, and 1% to 2% is inorganic salts and organic matter. There are small flakes suspended in the amniotic fluid, including fetal fat, epithelial cells shed by the fetus, and vellus hair. Hair, a small amount of white blood cells, albumin, urate, etc., as well as a large number of hormones and enzymes in the amniotic fluid.
What is amniocentesis
Amniocentesis uses a simple instrument to remove a few milliliters of amniotic fluid produced during pregnancy and perform tests to determine the health of the fetus. It is a diagnostic method that mainly uses fetal exfoliated cells, villus cells or fetal blood cell cultures in amniotic fluid to diagnose fetal chromosomal diseases and gender-linked genetic diseases. Generally suitable for prenatal diagnosis in the second trimester.
What does amniocentesis detect?
Amniocentesis is an effective prenatal screening method for fetal karyotypingAnalysis, chromosomal genetic disease diagnosis and gender identification, amniotic fluid cell DNA can also be used for genetic disease diagnosis and metabolic disease diagnosis. Determination of alpha-fetoprotein in amniotic fluid can also diagnose fetal open neural tube malformations. At present, amniocentesis in the second trimester is mainly used to check whether the fetus has chromosomal abnormalities to reduce the risk of giving birth to stupid children. Because if such congenital defects cannot be screened out, the children will not be able to take care of themselves in the future, which will bring a heavy burden to the family. The most common type of chromosomal abnormality is congenital stupidity, also known as Down syndrome, of which we may learn more. Down syndrome screening is a routine prenatal check-up item, and risk control is relatively strict. A high risk of Down syndrome screening does not necessarily mean that the fetus has Down syndrome, and it can be further diagnosed through amniocentesis.
Determine whether the fetus is mature in late pregnancy, i.e.
When the expected date of delivery cannot be determined, amniotic fluid can be extracted at an appropriate time for analysis to determine the degree of fetal maturity. At this time, amniocentesis can determine blood type, bilirubin, lecithin, sphingomyelin, placental prolactin, etc. to understand whether there is blood type incompatibility, hemolysis, fetal lung maturity, skin maturity, placental function, etc.
When is the best time to do amniocentesis?
The best time to do amniocentesis is between 16 and 22 weeks of pregnancy. At this time, the amount of amniotic fluid is relatively large and the fetus is small. When using a needle to extract amniotic fluid, it is not easy to puncture the fetus, and extracting 20 to 30 ml of amniotic fluid will not have adverse effects on the development of the fetus. The most important thing is that the amniotic fluid during this period contains Fetuses have many viable cells and the success rate of cell culture is high. This method is mainly used for prenatal diagnosis of fetal chromosomal abnormalities, such as trisomy 21, trisomy 18, trisomy 13, and Turner syndrome. It can also be used to diagnose hereditary metabolic diseases, such as amphetamines. Acidketonuria, albinism, galactosemia, favismosis, etc. DNA mutation analysis can also be performed to diagnose single gene diseases, such as brachydactyly, color blindness, thalassemia, hemophilia, etc.
Amniocentesis is a process in which, under the guidance of B-ultrasound, a lumbar puncture needle is used to vertically puncture the abdominal wall of a pregnant woman, enter the amniotic cavity, and extract some amniotic fluid.
What are the risks of amniocentesis?
Any clinical surgery and operation may have risks, and amniocentesis is no exception. Bleeding, amniotic fluid leakage, infection, fetal damage, miscarriage, intrauterine fetal death, pain and stress, etc. may occur. Stimulation can induce cardiovascular and cerebrovascular accidents in pregnant women. There are also various reasons that lead to failure of puncture and failure of amniotic fluid cell culture, making it impossible to make a diagnosis.
Based on the above reasons, although this operation is simple and easy to perform, due to its inevitable risks, prudent choices must be made before the operation, and caution must be used during the operation. In addition, when necessary, pregnant mothers should follow the doctor\’s advice and undergo amniocentesis to avoid the situation in Case 1.