Chorionic villus biopsy: what patients should know

It is also called chorionic villus sampling, or CVS. A specialist removes a small placental sample through the abdomen or through the cervix, depending on the placenta's position and clinical circumstances.

Placental cells usually carry the same chromosomes as the pregnancy, so laboratory analysis can look for the specific condition being investigated. CVS is different from a routine cancer biopsy and does not assess every possible health or developmental problem.

Results may be clear, uncertain, or occasionally require confirmation with another prenatal test. A genetics professional can explain what was tested, what was not tested, and what a particular finding could mean for the pregnancy and family.

Before the appointment, check whether you should arrive with a full bladder and whether any regular medicines need special instructions. Tell the team about blood-thinning medicines, allergies, your blood group if known, and any current bleeding or infection symptoms.

Ultrasound guides the sampling route. Cramping or light spotting may occur afterward, and the clinic should provide activity guidance plus a number to call. Arrange support for the journey home if you feel anxious or uncomfortable.

Seek prompt medical advice after CVS for heavy or increasing bleeding, leaking clear fluid, fever, chills, severe or worsening abdominal pain, regular contractions, or feeling markedly unwell. Use emergency services for collapse, severe breathing difficulty, or bleeding that feels unmanageable.

Ask which condition the laboratory will test for, why CVS is being offered now, how the sample will be taken, when results may return, and what choices would follow each possible result. You can also ask how this differs from other prenatal testing options.