Prenatal diagnosis refers to the application of imaging, biochemistry, cytogenetics, molecular biology and other methods and detection means to diagnose some congenital malformations or hereditary diseases before the birth of the fetus, so as to prevent the birth of fetuses with serious hereditary diseases, mental retardation and congenital malformations.
Under what circumstances do you need to go to the prenatal diagnosis center for consultation?
1. One of the husband and wife is a patient with X-linked genetic diseases or a carrier of pathogenic genes, or has a family history of X-linked genetic diseases;
2. Young men and women or married couples who are going to get married due to genetic diseases;
3. Couples or blood relatives who have given birth to severely deformed children or have a family history of genetic diseases;
4, long-term exposure to adverse environmental factors, virus infection, improper medication and pregnant women with certain chronic diseases;
5. Pregnant women with assisted reproductive pregnancy and multiple pregnancies;
6. Premarital examination and consultation for young men and women;
7. Couples who have been infertile for many years after marriage;
8. Unexplained mental retardation;
Older pregnant women over 9.35 years old;
10, with a history of habitual abortion and stillbirth;
1 1, with a history of exposure to fetal teratogenic factors in early pregnancy;
12, too much or too little amniotic fluid;
13, with a history of chromosomal abnormalities in children;
14, one of the couples is balanced translocation or chimera;
15, with a history of delivery of children with neural tube malformation or limb malformation;
16. Birth history of children with congenital metabolic abnormality.
Experts remind! How do you know if you have a fetus with birth defects?
First, prenatal screening
1, Down's Screening: During the period of 1 1+6 weeks, 2ML of venous blood of pregnant mothers is taken for detection, which is a non-invasive detection method for the fetus. If the pregnant mother's serum screening is positive, amniotic fluid examination is needed to make a clear diagnosis and treatment. Down's screening can also check high-risk pregnant women with aqueduct defect, 18 body syndrome and 13 body syndrome. Results The accuracy rate was 60-70% (free of charge).
2.NT examination: In the early pregnancy (1+6 ~13+6 weeks), the thickness of the fetal neck zona pellucida was detected by ultrasound, so as to make early diagnosis and judge whether the fetus has the possibility of chromosome abnormality. If the thickness of the cervical zona pellucida exceeds 2.5mm, it means that the fetus has some chromosome disease or dysplasia.
3. Non-invasive gene detection: 5ML of blood was taken from 0/2 week of pregnancy to 22+6 weeks of pregnancy for detection, from which free DNA was extracted, and the risk rate of fetal chromosome aneuploidy was obtained, with an accuracy rate of over 98%.
4. Whole body ultrasound examination: The most important "whole body ultrasound examination" during the whole pregnancy should be done at 22-26 weeks, commonly known as "ovulation abnormality". The purpose of this ultrasound is to check whether there are any major malformations in the fetus. At 28-34 weeks, the deformity was examined for the second time.
Second, what is a chromosomal disease?
There are 23 pairs (46 chromosomes) of normal human cells, including 22 pairs of autosomes and sex chromosomes 1 pair (male: xy; Female: XX). Changes in the number of chromosomes (more or less than one) or structural abnormalities (deletion or duplication) may lead to chromosome diseases.
In the picture below, the blue circle is the structural abnormality of chromosome deletion and repetition, and the red circle is the chromosome number abnormality.
What are the hazards of chromosomal abnormalities?
1, special face or organ defect
2. Mental retardation
3. stunting
4. Muscle weakness (nerve abnormality)
5. Social barriers
Three. Interventional prenatal diagnosis
How does interventional prenatal diagnosis work? How to choose the specific operation time?
The whole process of prenatal diagnosis operation is carried out under the guidance of ultrasonic monitoring, avoiding the fetus, determining the position of placenta and fetal condition, and then puncturing, so it will not hurt the fetus.
1, villus biopsy during pregnancy 1 1- 13+6 weeks.
2. Amniocentesis was performed in 0/6-24 weeks from Kloc.
3. Umbilical vein puncture after 24 weeks of pregnancy.
How do you know if you are pregnant with a child with Down syndrome?
1, Down's Screening: During the period of 1 1+6 weeks, 2ML of venous blood of pregnant mothers is taken for detection, which is a non-invasive detection method for the fetus. If the pregnant mother's serum screening is positive, amniotic fluid examination is needed to make a clear diagnosis and treatment. Down's screening can also check high-risk pregnant women with aqueduct defect, 18 body syndrome and 13 body syndrome. Results The accuracy rate was 60-70% (free of charge).
2.NT examination: in the first trimester of pregnancy,1+6 ~13+6 weeks, the thickness of cervical zona pellucida was screened, and the fetus was diagnosed early to judge whether it was abnormal. If the thickness of the cervical zona pellucida exceeds 2.5 mm, it will cause some chromosomal diseases or dysplasia in the fetus.
3. Non-invasive gene detection: 5ML of blood was taken from 0/2 week of pregnancy to 22+6 weeks of pregnancy for detection, from which free DNA was extracted, and the risk rate of fetal chromosome aneuploidy was obtained, with an accuracy rate of over 98%.
4. Four-dimensional ultrasound examination in the second and third trimester of pregnancy.
So what are the clinical symptoms of Down syndrome? Please follow Chen and the hospital experts to understand.
1. Children with Down syndrome are characterized by severe mental retardation, with general intelligence only 30-70% of that of normal people, stunted limbs, special face, wide eye distance, flat nose, short stature and bone age behind their age.
2. Up to now, there is no very effective treatment for Down syndrome, and the life span of patients is shorter than that of normal people. Generally, when you live to 30-40 years old, there will be senile diseases, and the family burden is serious.
3. Digestive organ malformation, such as congenital esophageal atresia, about 65,438+00% of children are accompanied by epilepsy, and about 40% are accompanied by congenital heart disease and other complications. Because of their low immune function, they are prone to various infections, and the incidence of leukemia has also increased by 10-30 times.
So what is thalassemia screening? Heze Michael Chen experts introduce you:
Thalassemia, referred to as thalassemia for short, is a hereditary disease, which is caused by the deletion or point mutation of human globin gene, resulting in the disorder of hemoglobin synthesis, which is manifested as hemolytic anemia in different degrees. There are two common types: α thalassemia and β thalassemia. In the high incidence areas of thalassemia in Guangdong and Guangxi provinces, epidemiological investigation shows that there are 1 thalassemia gene carriers in every 6 people in Guangdong province; 1 person in every 250 families is at risk of severe thalassemia. 1 child in every 850 fetuses suffers from severe thalassemia.
Thalassemia is a "preventable and refractory" genetic disease, and prevention is the main method. Mild thalassemia can be treated asymptomatic, while severe thalassemia requires expensive hematopoietic stem cell transplantation with low success rate. Without hematopoietic stem cell transplantation, patients can only rely on blood transfusion and long-term use of iron remover to maintain their lives. Even so, after long-term blood transfusion, more and more iron will be deposited in organs such as liver and spleen, which will lead to failure and death of these organs.
If we can clearly understand our genetic background before marriage and do a good job in prenatal screening and diagnosis of thalassemia, we can effectively reduce the chance of the next generation suffering from severe thalassemia.
If both husband and wife are not carriers of thalassemia gene, their next generation will not have this gene.
If only one of the husband and wife is a thalassemia gene carrier, then every pregnancy, the child has a 50% chance of becoming a thalassemia gene carrier.
If both husband and wife are thalassemia gene carriers, their children have a 25% chance of being normal every pregnancy, a 50% chance of being thalassemia gene carriers and a 25% chance of suffering from severe thalassemia.
Tips: Through the introduction of gynecologists in Hehe Hospital, you must have a certain understanding of relevant knowledge. If a female friend has other questions, she can directly come to the hospital to consult a gynecologist. Experts will give you satisfactory service!