How long does it take to check chromosomes during pregnancy?

For families expecting a newborn, they have to go through tedious pregnancy preparations before pregnancy, and after pregnancy they have to worry about whether the fetus is developing healthily. Therefore, the birth of a newborn is hard-won for any family. The purpose of pregnancy chromosome check is to rule out congenital diseases caused by chromosomal abnormalities. It is mainly conducted between 14 and 40 weeks of pregnancy, and most of the time the test is done by drawing amniotic fluid from the pregnant woman.

How long after pregnancy can I do chromosome test?

After 14 weeks, and no later than 20 weeks. The people who need to do maternal chromosome testing are mainly older mothers over 35 years old, or pregnant women who are suspected to be at high risk of fetal defects after Down syndrome screening. They may also need to do an amniocentesis within 16-20 weeks of pregnancy. During this examination, the doctor will use a very fine needle to pierce the abdomen and enter the uterus, and then extract a small amount of amniotic fluid from the amniotic sac for examination. The cells in the amniotic fluid will be used to check for chromosomal problems. This test has a relatively high accuracy rate.

What is chromosome testing?

Chromosome examination is a method of detecting whether there are abnormalities in the number or structure of chromosomes. It plays an important role in the diagnosis, treatment, prognosis and monitoring of recurrence of blood diseases. As an important examination during pregnancy, chromosome examination can predict the risk of giving birth to offspring with chromosomal diseases, detect genetic diseases early, and whether the individual has chromosomal abnormalities or common sex chromosome abnormalities that may affect fertility, so as to take active and effective intervention measures.

How to do chromosome test

Peripheral blood was cultured at 37°C for 72 hours under the action of the cell growth stimulating factor, phytohemagglutinin (PHA), to obtain a large number of dividing cells. Colchicine was then added to stop the dividing cells at metaphase to facilitate observation of chromosomes. The cells were then hypotonic expanded to reduce the entanglement and overlap between chromosomes. Finally, the cells were fixed on a glass slide with methanol and glacial acetic acid, and the structure and number of chromosomes were observed under a microscope. The normal male chromosome karyotype is 44 autosomes plus 2 sex chromosomes X and Y, and is often represented by 46, XY in the examination report. The autosomes of normal women are the same as those of men, and there are two XX sex chromosomes, usually represented by 46,XX. 46 represents the total number of chromosomes. A number greater than or less than 46 is considered an abnormal chromosome number. The missing sex chromosome is often represented by O