Is it necessary to do amniocentesis after non-invasive

Some pregnant women need to do amniocentesis during pregnancy. It is said that this pregnancy test is painful and has certain risks. Non-invasive DNA test is a common test. This test is very related to Down syndrome screening. It is mainly used to check whether the chromosomes of the fetus are normal. So if the non-invasive test is passed, do you still need to do amniocentesis?

Is it still necessary to do amniocentesis if the risk is low with non-invasive DNA? Regarding this question, relevant people said that under normal circumstances, non-invasive DNA only checks three pairs of chromosomes and is only related to Down syndrome. For specific situations, it is recommended to consult a doctor before making a decision, because everyone's situation is different.

Do I need amniocentesis for low-risk non-invasive DNA testing?

Because non-invasive DNA only checks three pairs of chromosomes and is only related to Down syndrome, while amniocentesis checks all chromosomes, which is the limitation of non-invasive DNA testing. If the baby’s problem is not related to Down syndrome, it cannot be detected through non-invasive testing.

Non-invasive DNA is a non-invasive test with no wounds, no risks, and will not cause miscarriage. Non-invasive DNA is a new technology that detects by drawing a certain amount of blood. It is not dangerous to either the mother or the fetus and is a relatively safe prenatal test. It is mainly used to check for Down syndrome.

Combine three-dimensional color ultrasound to rule out deformities. Blood type cannot be checked through non-invasive DNA, and there is no point in checking it now, so there is no rush.

Non-invasive prenatal genetic testing is performed by collecting peripheral blood (5 ml) from pregnant women, extracting free DNA, using a new generation of high-throughput sequencing technology, and combining it with bioinformatics analysis to determine the risk of the fetus suffering from chromosomal aneuploidy (trisomy 21, also known as Down syndrome, trisomy 18, trisomy 13). The best detection time for this method is in the early and middle stages of pregnancy. It has the characteristics of non-invasive sampling, no risk of miscarriage, high sensitivity, and high accuracy.

Advantages of non-invasive DNA

As the most widely used prenatal screening method for Down syndrome, Down syndrome screening (abbreviated as Down screening) mainly uses serum biochemical values ​​to calculate the risk of the fetus suffering from trisomy 21, trisomy 18 and neural tube defects. The detection rate in China is about 60%. One of the main groups of pregnant women that non-invasive DNA prenatal testing targets is pregnant women at high risk of Down syndrome screening.

1. High safety factor. Invasive prenatal examinations that use invasive sampling, such as amniocentesis, chorionic villus sampling, or umbilical vein blood puncture, can easily cause intrauterine infection and increase the risk of miscarriage. Non-invasive DNA prenatal testing only requires 5-10 ml of peripheral venous blood from the pregnant woman to screen for developmental abnormalities in the fetus.

2. The test results are more accurate. Based on the new generation of high-throughput sequencing and information analysis technology to screen for chromosomal aneuploidy diseases, the accuracy rate of non-invasive DNA prenatal testing is estimated to reach more than 90%, greatly reducing the risk of subsequent trauma caused by false positives and missed results in Down syndrome screening.

3. Detect more chromosomes. Non-invasive DNA can screen for three diseases: trisomy 21, trisomy 18 and trisomy 13, and can also provide hints for other chromosomal abnormalities. However, Down syndrome screening can only detect two chromosomal aneuploidy diseases: trisomy 21 and trisomy 18.

4. The screening gestational age range is wider. The suitable gestational age for early pregnancy Down syndrome screening is 11-13 weeks, the suitable gestational age for mid-pregnancy Down syndrome screening is 15-20 weeks, and the suitable gestational age for non-invasive prenatal genetic diagnosis can last until pregnancy (22 weeks + 6 days).