How to do fetal chromosome test

Normal people have 23 pairs of sex chromosomes, but many people have chromosome deletions or sex chromosome additions. Instruments and equipment cannot detect this disease, and many sex chromosome diseases in the world cannot be cured. Therefore, many parents will check the chromosomes of their children when they are born. So, how to check the chromosomes of the fetus?

How to check chromosomes in the fetus

Fetal chromosome testing can begin around the tenth week of pregnancy through a villus sampling test, while amniotic fluid testing is usually done after the sixteenth week of pregnancy. The actual method used for fetal chromosome examination will be determined based on the possibility of chromosomal abnormalities and the conditions of the pregnant woman and fetus. However, you can rest assured that no matter which method is used for fetal chromosome examination, it is safe.

There are many things to do when checking chromosomes. Usually, you cannot check chromosomes during pregnancy. You can check chromosomes after the baby is born. The chromosome check during pregnancy is a professional check for some diseases. If there is no family genetic inheritance, then the chromosome check is unnecessary. So, how to check chromosomes better?

Peripheral blood was cultured at 37°C for 72 hours in the presence of a cell growth stimulating factor, phytohemagglutinin (PHA), to obtain a large number of dividing cells. Colchicine was then added to stop the disrupted cells in the middle and late stages of disruption, making it easier to observe the chromosomes. The cells were then osmotically expanded to reduce the entanglement and overlap of the chromosomes. Finally, ethanol and acetic acid were used to fix the cells on a slide, and the structure and number of the chromosomes were observed under a microscope.

The normal male karyotype is 44 autosomes plus 2 chromosomes X and Y, which is often expressed as 46, XY in the test sheet. The autosomes of normal women are the same as those of men, with 2 XX chromosomes, and the common expression is 46,XX. 46 represents the total number of sex chromosomes. Any number above or below 46 is considered an abnormality in the number of sex chromosomes. The missing chromosome is usually expressed as O.