Most of the amniocentesis examinations are done between 16 and 22 weeks of pregnancy because the fetal cell viability is the best during this period. It is also possible to determine the presence of fetal malformations. In general, amniocentesis can be performed if there is a suspicion of genetic disorders or factors that may cause fetal malformations. Amniocentesis can determine the blood type of the fetus, as well as the level of bilirubin and lecithin in the fetus. The amniocentesis can detect hypoxia and compression of the fetus. If the fetus is found to be significantly hypoxic or distressed, immediate measures should be taken to avoid these phenomena in order to save the fetus, which could lead to fetal death if not detected by amniocentesis. In fact, in many cases, parents are very interested in the sex of the fetus and are driven by this curiosity to perform amniocentesis, which has a very high accuracy rate in identifying the sex of the fetus. Amniocentesis is also an option if there is a suspicion of fetal growth retardation or abnormal development. What are the conditions for amniocentesis? Amniocentesis is performed to screen for chromosomal abnormalities in order to reduce the number of births of dumb and stupid babies. It is generally recommended for high-risk women over 35 years of age. Amniocentesis is not mandatory, but it is recommended for the health of the next generation. If you are under 35 years of age but have been screened intravenously for Down’s syndrome and are found to be at high risk, you should also have an amniocentesis to be on the safe side. In addition, pregnant women who have had a child with a chromosomal abnormality must have an amniocentesis; and pregnant women who have been exposed to toxic substances and radiation during pregnancy, the fetus can only and may be adversely affected, so amniocentesis is also mandatory. How is amniocentesis done? Generally, amniotic fluid tests do not require an empty stomach, but it is best to go in the morning, because the puncture cannot be done immediately after registration. After these tests, a decision can be made whether or not to perform the puncture. The steps of amniocentesis are as follows: Pregnant women with indications should first undergo ultrasound to determine the position of the placenta and fetal condition and to avoid accidental injury to the placenta. After selecting the entry point, disinfect the skin, lay a sterile towel, apply local anesthesia, and use a lumbar puncture needle with a needle core to puncture vertically at the selected point; when the needle passes through the abdominal wall and uterine wall, there is a feeling of emptying twice, remove the needle core; aspirate 2 ml of amniotic fluid with a 2 ml syringe and discard it, as this section of amniotic fluid may clearly contain maternal cells; then aspirate 20 ml of amniotic fluid with an empty 20 ml needle, put it in 2 sterile test tubes and cover it; remove the needle, cover it with sterile gauze, and perform amniocentesis. The needle is removed, covered with sterile gauze, compressed for -minutes, and the pregnant woman rests in bed for 2 hours. The actual amniocentesis is usually done only when the pregnant woman has not passed the Down’s syndrome screening, but it is not necessary to do the puncture under normal circumstances. The amniocentesis is mainly for senior pregnant women, those with various high-risk factors during early pregnancy, those with high risk of Down’s syndrome screening and those who have previously delivered a child with severe congenital malformations, and those with familial genetic disorders. The mother-to-be’s poor nutrition will lead to fetal growth retardation or miscarriage, while excess nutrition may also lead to infinite fetuses and various complications, resulting in obstructed labor, which should not be done for amniocentesis. The mother-to-be’s diet must be rich in various nutrients, and the nutrients must be reasonably well-distributed. Before the amniocentesis, the pregnant woman should pay attention to rest and maintain a good mental state, because in the process of amniocentesis, the suction tube has to pass through the uterus, which may cause uterine contractions, resulting in preterm labor. So you can take some fetal protection medicine in advance. Fetal protection medicine can inhibit contractions, and if the pregnant woman has cardiovascular disease, she should not do amniocentesis due to pain, tension and other stimuli. During pregnancy, especially if the white blood cells are too low and the platelets are too low, it is not advisable to undergo amniocentesis. If the test is forced, it will easily cause infection and bleeding. During pregnancy, if you are not uncomfortable and everything is normal, then you do not need to undergo amniocentesis during normal testing, but pregnant moles need to undergo regular Down’s syndrome screening and 3D ultrasound. If there is a high risk of trisomy when doing the Down’s syndrome screening, then it is very necessary to do the amniocentesis test, if not, the fetus may suffer from the problem of trisomy 21, so do not be slow, it is recommended to choose a hospital with better medical conditions for the examination. The actual fact is that if you’ve got a high risk of developing a child after the Down’s syndrome screening, you’ll be able to say that the child may have a developmental abnormality, and your doctor will recommend amniocentesis. There is another situation where doctors may recommend amniocentesis, and that is if one of the spouses has a history of genetic defects during the pregnancy, in which case the doctor may recommend amniocentesis to check for abnormalities in the baby’s DNA. The main principle of amniocentesis is to extract amniotic fluid from the fetus by puncturing the fetal membranes under the close observation of ultrasound if there is a suspected abnormality in the development of the fetus, and only through this can we further confirm whether there is a congenital abnormality in the development of the child. PS: Another role of amniocentesis is to do paternity testing, for example, some men suspect that the fetus in the wife’s womb is not their own, then in this case can be extracted through amniocentesis, and then DNA determination, this test is also a kind of paternity testing.