When is the best time to do amniocentesis? Time is of the essence.

Many expectant mothers know about amniocentesis, which is a method used to check whether the baby in their belly is healthy. However, there are many related matters that need to be understood when conducting this method. For example, grasping the correct examination time is the most important. So when is the best time to perform amniocentesis?

1. The best time to draw amniotic fluid for prenatal diagnosis is between 16 and 20 weeks of pregnancy. Because the fetus is small at this time and there is relatively more amniotic fluid, the fetus floats in the amniotic fluid with a wider amniotic fluid belt around it. It is not easy to injure the fetus when the amniotic fluid is extracted with a needle. Extracting 20 ml of amniotic fluid only accounts for 1/20 to 1/12 of the total amniotic fluid, which will not cause the uterine cavity to suddenly shrink and cause miscarriage. Moreover, the proportion of active cells in the amniotic fluid is the largest during this period, and the cell culture survival rate is high. It can be used for slide preparation, staining, fetal chromosome karyotype analysis, chromosome genetic disease diagnosis and gender determination, and amniotic fluid cell DNA can also be used to diagnose genetic and metabolic diseases. By measuring alpha-fetoprotein in amniotic fluid, it is also possible to diagnose open neural tube defects in the fetus.

2. Amniocentesis: Under the guidance of ultrasound, a thin needle is passed through the pregnant woman's belly, uterine wall, into the amniotic cavity, and some amniotic fluid is extracted. This process is called "amniocentesis."

3. Amniocentesis is a method commonly used both at home and abroad. Before amniocentesis, B-ultrasound is used to locate the fetus and placenta. Then, avoiding the placenta, the amniotic fluid is removed by puncture after anesthesia at the place with more amniotic fluid. After all, this is a stimulation to the mother and fetus. Therefore, pregnant women with threatened miscarriage and pelvic and uterine infection are not suitable for this examination. It is definitely risky, but its total risk rate, the risk of causing fetal miscarriage, generally speaking, does not exceed 1%.