Do you need a referral for chorionic villus sampling?

Chorionic villus sampling, or CVS, takes a small sample of placental tissue during pregnancy for diagnostic genetic testing. A maternal-fetal medicine team reviews why testing is being considered, explains what the result can and cannot show, and discusses alternatives. Ultrasound is used during the procedure to guide the clinician. Referral allows the team to confirm that the timing, pregnancy details, and available laboratory testing are appropriate. It does not mean that a condition has been confirmed.

Ask your obstetrician, midwife, or prenatal care clinician to explain the referral pathway and expected appointment timing. Bring previous scan reports, screening results, family medical history, and a list of medicines. At the consultation, ask how the sample will be collected, when results may be discussed, and what support is available while waiting. Tell the team about bleeding, pain, fluid leakage, allergies, or any concern about the procedure before the appointment.

During pregnancy, seek urgent maternity advice for vaginal bleeding, fluid leakage, severe or persistent abdominal pain, fever, fainting, or regular contractions. After CVS, contact the maternity team urgently if you develop heavy bleeding, worsening pain, fever, fluid leakage, or feel acutely unwell. These symptoms need assessment and should not be managed by waiting for the planned results call.

Ask why CVS is being offered, whether another test could answer the same question, what the procedure can detect, and how results will be communicated. Ask which symptoms after the procedure require immediate contact with the maternity team.