It’s an examination performed on the placental tissue in the early stages of development, and is performed by the aspiration of chorionic villi through a needle introduced via the trans-abdominal cavity.

The examination is performed in the surgery and requires no preparation beforehand (e.g., fasting or empty bladder). It’s recommended that you take an antibiotic prophylaxis for three days before the exam.
Initially, a preliminary trans-abdominal ultrasound is performed, and then the abdomen is disinfected, and finally the placenta tissue is removed using an ultrasound-guided needle.
The technique is not so painful and the extraction takes about 10 minutes.
After the tissue has been removed, the patient is advised to remain under observation (with ultrasound checks) for a couple of hours before leaving the facility. Complete rest is prescribed for the next three days.

Chorionic Villus Sampling is performed by the 10th to the 12th week of pregnancy. It can be performed even in more advanced periods, and in this particular case it is related to a placental biopsy.

It allows you to diagnose with certainty chromosomal abnormalities of the unborn child (e.g., Down syndrome or trisomy 21), the most frequent genetic diseases (fragile X syndrome, cystic fibrosis, genetic deafness, thalassemia, Duchenne muscular dystrophy, etc.) and upon request, genetic compatibility (paternity test).

This invasive procedure involves a 0.5% risk of miscarriage.