Chorionic villus sampling

Chorionic villus biopsy
For this test, chorionic villi (tiny projections of placental tissue) are removed from the placenta to be certain that your baby does not have any chromosomal abnormalities.


Chorionic villus sampling can be performed after week 11 of your pregnancy.

Course of the procedure

Duration: 30 minutes

Chorionic villus sampling is carried out at the ultrasound centre.

  • First, the mother will undergo an ultrasound examination.
  • Depending on the accessibility of the placenta, the doctor can choose from two different techniques to aspirate some villi using a syringe.
    • Transabdominal: puncturing the abdominal wall with a thin needle to reach the placenta.
    • Transcervical: via the vagina with a fine tube that is inserted into the uterus and up to the placenta.


The time required for the laboratory analysis of the villi depends on the condition being tested, varying from 3 days to 3 weeks. Your doctor can provide detailed information about this.

In 1% of cases, the results are not interpretable or the villi do not contain enough dividing cells for the test to proceed. In these situations, an amniocentesis procedure will still be recommended.

Risk factors

Chorionic villus sampling carries an additional risk of miscarriage of about 0.5%.


After chorionic villus sampling, you may experience some cramps in your lower abdomen. You may also suffer some blood loss for a few days after transcervical chorionic villus sampling.

About chorionic villus sampling

Because the villi (chorionic villi) from the placenta have the same genetic composition as the fetus, it is possible to obtain information about the health of the fetus by examining the villi tissue.

Last edit: 15 June 2021