Why Should Chorionic Villus Sampling (CVS) Be Performed?
Chorionic villus sampling is performed between 11 and 14 weeks of gestation to diagnose some chromosomal and genetic diseases. It is often performed in the first trimester (first 3 months) to investigate whether increased nuchal translucency, increased risk on double screening test, pathological/abnormal findings on early ultrasound examination, or a family history of genetic disease is also present in the fetus.
Because the placenta and fetus arise from the same cells, the chromosomes of the cells in the placenta and the cell chromosomes of the fetus are generally considered to be identical.
How Is Chorionic Villus Sampling (CVS) Performed?
The site of the procedure is anesthetized with a local anesthetic. Chorionic villus sampling is performed under ultrasound guidance, and 10-30 mg of villus samples are taken from the fetal placenta, in an amount that does not affect the fetus, by piercing the abdominal wall and uterine wall of the expectant mother with a needle under sterile conditions. The procedure is short and a second access is rarely needed. The gestational sac is not entered during the procedure, and there is no possibility of the needle touching the baby. The procedure is terminated after the fetal heartbeat is checked.
What Can Happen After A Chorionic Villus Sampling?
In the first few days, you may experience groin pain or light bleeding. Usually, pregnancies are uneventful, and acetaminophen-based pain relievers may help. However, if you have excessive pain or bleeding or your temperature rises, return to the clinic immediately.
The rate of pregnancy loss and miscarriage due to chorionic villus sampling (CVS) is 0.5-1% (1 in 100-200 procedures) and usually occurs within the first 5 days after the procedure. The fact that this rate is higher than amniocentesis is not due to the high risk of the procedure, but to the fact that it is performed during the first weeks of pregnancy, when miscarriages are more common. Miscarriages can be caused by opening of the gestational sac, transfer of microbes to the intrauterine tissue after the procedure, and bleeding from the uterine wall.
