Pregnancy class
PREGNANCY
— What exactly is "piercing"? —
Before being born, every baby will lie in their mother's belly and absorb nutrients and grow up slowly. If you encounter uncertainties in your baby's development, you need to put the small operation of "puncture" on the agenda.
Puncture refers to a diagnostic and therapeutic technique in which a needle is inserted into different parts of the body cavity to extract secretions for testing. Punctures that often meet expectant mothers include villous punctures, amniotic fluid punctures, umbilical cord blood punctures, and so on. With the maturity of medical technology, the puncture process is usually relatively safe, but there is still a slight risk of miscarriage and infection, and there is a probability of puncture failure.
Let's take a quick look at the differences between each "puncture".
Villous puncture
Abbreviated as velvet wear
Main role: to confirm the presence or absence of chromosomal abnormalities in the fetus
Suitable population: children who have given birth to chromosomal abnormalities, one of the spouses is a carrier of abnormal chromosomal abnormalities or balanced ectopics, and the sex of the fetus is determined in the second trimester
Examination time: 11-14 weeks of gestation Sample contents: placental chorionic tissue cells
The most common villous punctures are transverse and ventral. Taking transvasive puncture as an example, under the premise of B ultrasound diagnosis, the doctor will pass a slender needle through the vagina and cervix into the placental villous part, and use an empty needle tube to aspirate a small amount of villi for examination, and about 2% of pregnant women may have amniotic fluid overflow or uterine contractions during the extraction process. At this time, if the extracted tissue is placed in the culture solution for observation, it can be found that its shape resembles villi.
The test report of villous puncture is normal, which can only prove that there is no abnormality in the baby's chromosomes, and cannot exclude diseases caused by other chromosomes, such as congenital heart disease, intellectual disability or cleft lip and palate. In other words, even if the chromosome test is normal, about 2% of babies are born with some physical abnormality. If doctors find that the diagnosis of villus sampling is unclear, they may recommend an amniocentesis to confirm the diagnosis.
Tip: You need to drink water before doing villous puncture, and the whole puncture process does not exceed 1 hour.
amniocentesis
Referred to as sheep wear
Main role: to carry out karyotype analysis of chromosomes, genetic problem analysis
Suitable for: advanced pregnant women over 34 years old; family history of Down syndrome, maternal blood Down syndrome is high (greater than 1/270), abnormal NT results or abnormal ultrasound examination
Examination time: 16-24 weeks gestation Sample contents: Amniotic fluid cells
The reason why amniocentesis is chosen at 16-24 gestational age is because the fetus is smaller and has more amniotic fluid at this time, and it is not easy to stab the fetus. At this time, the proportion of viable cells in amniotic fluid is the largest, and the survival rate of cell culture is high, which can cope with different examination needs with an accuracy rate of more than 99%.
Before doing the amniocentesis, the doctor will confirm the position of the fetus through the B ultrasound, then coat the pregnant woman's abdomen with alcohol, cover the abdomen with a surgical cloth with holes, and directly use a thin waist piercing needle to pass through the abdominal wall and uterine wall according to the positioning. When the needle is just pierced into the body, the mother will feel a slight pain, but it is similar to the pain level of the fingertip blood collection, and the expectant mother does not need to be too nervous.
After the lumbar piercing needle with the needle core reaches the specified position, the doctor will take 2ml and 20ml of amniotic fluid for different examinations.
Tip: There is no need to drink water and urinate before doing amniocentesis, and the total process does not exceed ten minutes.
Umbilical cord blood puncture
Main role: further verification of villous puncture and amniocentesis test results, can check the fetal spine for malformations
Suitable people: Expectant mothers who have previously had abnormal test results and need further confirmation
Examination time: after 20 weeks of pregnancy Sample contents: cord blood cells (baby's blood)
Cord blood puncture determines the site of the puncture based on the location of the placenta, and before the cord blood puncture is done, the doctor will ask the patient to perform a blood routine and kidney function test. Puncture and blood are drawn after the B ultrasound determines the position of the fetal baby, and the time required is not more than half an hour.
No matter what kind of puncture minor surgery, the really important examination has just begun after the sample is taken. According to the various indicators of the expectant mother, the doctor will conduct chromosomal karyotype analysis, genomic copy number mutation detection, and gene targeting testing.
Karyotype detection of chromosomes is carried out by culturing cells, making tablets and dyeing, and then visually observing whether there is one more or one less chromosome in the baby under the microscope.
Genomic copy number variation detection can not only see abnormal chromosome numbers, but also find the addition and deletion of tiny chromosome fragments.
Gene-targeted testing is a targeted test for a single-gene disease. For example, if ultrasound B finds polycystic lesions, the detection will be carried out around genes associated with polycystic lesions. If the ultrasound test results appear "symptoms are unknown and cannot be judged", doctors will also perform a wide-net whole genome sequencing to screen for the cause.
Finally, the following small TIP is given to expectant mothers:
In addition to the three types of puncture surgery, Both Down screening and noninvasive DNA testing can test the fetal baby's chromosomes to varying degrees. Among them, Down's screening is suitable for all pregnant mothers, and if conditions permit, non-invasive DNA testing can also be performed.
If you are worried about the baby's development, you want to have a better understanding of the baby's development through puncture, you can take a relatively safe approach, the safety of these three is ranked as velvet puncture > sheep puncture > umbilical cord blood puncture. Among them, the advantage of velvet puncture is early examination, the disadvantage is that it is relatively painful; the advantage of sheep wear is that the operation is simple, and the disadvantage is that the problem is found late; and the advantage of cord blood puncture is that the test results are meticulous and accurate, and the disadvantage is that the risk is the highest of the three. Expectant mothers can make choices based on doctors' advice and actual situations.
Puncture surgery is not a test that all pregnant women need to do, and if there are no abnormalities in the basic examination, it can be skipped.
All the expectant mothers who are pregnant with new births have thousands of worries in their hearts, hoping that the baby is healthy and worried that ta's nutrition is not enough. I hope that this summary can add a certainty to the path of expectant mothers.
Of course, it is important to choose the right examination, but it is more important to maintain a good mood and a healthy diet, and I wish you a good pregnancy!
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