Hello everyone, I am Dr. Zeng of Liu Xiangyuan's team. After fetal arrest occurs, many couples will have chromosome tests to determine whether chromosomal abnormalities are causing fetal arrest. So what should chromosome tests be done? What are the chromosome test items?
How do chromosomes work?
To check the chromosomes, you can do a venous blood test, or you can take tissue for a chromosome test. People who are infertile or have recurrent abortions usually need to be examined for chromosomes.
Chromosome examination includes prenatal screening, prenatal diagnostic methods, screening is through Down's screening, non-invasive genetic testing, the examination of abnormal risk values of fetal chromosomes, and the peripheral blood of pregnant women is drawn, so this test is noninvasive.
However, screening is not a complete diagnosis, and the high risk indicates that the fetus is at increased risk of chromosomal abnormalities, suggesting the need for further prenatal diagnosis and amniocentesis.
Prenatal diagnosis can determine exactly whether the fetal chromosomes are normal, and if prenatal screening suggests risk, there is no need to do prenatal diagnosis and amniocentesis.
However, some couples who have chromosomal abnormalities themselves, or have a bad maternal history of chromosomal abnormalities, need to do amniocentesis to check the fetal chromosomal core, copy number variations, and genetic abnormalities.
What are the chromosome tests?
Usually, if you only do routine chromosomal examinations, you only need to test the blood and analyze the blood for immune factors, hereditary factors, infectious factors, endocrine factors, anatomical factors, etc.
However, if there has ever been a experience of fetal cessation, it may be caused by abnormal chromosomal development. In this case, if you do a chromosome examination, you should also check the number of chromosomes and the structure of the chromosomes to see if they are abnormal. If there are no chromosomal abnormalities, you can try to conceive.
When is a chromosome test done?
If you are planning to have a baby, it is best to test both husband and wife before pregnancy, and if you are already pregnant, it is best to do an amniocentesis chromosome test at 16-20 weeks.
Because the fetus is small at this time, there is more amniotic fluid, and the fetus floats around the amniotic fluid with a wide band of amniotic fluid, and it is not easy to stab the fetus when puncturing the amniotic fluid with a needle. Moreover, the proportion of viable cells in amniotic fluid during this period is the largest, and the survival rate of cell culture is high, so the test results will be more accurate. Once any problem is found, it needs to be treated in time.