Chorionic villus sampling, or CVS, is one of the prenatal genetic testing options offered to pregnant women, often discussed alongside amniocentesis as a diagnostic (rather than screening) test. For women pregnant after 35, when the likelihood of certain chromosomal conditions increases somewhat with age, CVS is a procedure that may come up early in prenatal care conversations. Understanding what the test actually involves can make the decision of whether to pursue it feel less abstract.
Deciding whether to have CVS, decline it, or opt for non-invasive screening instead is a personal decision that depends on your individual risk factors, values, and how you plan to use the information. There’s no universally “right” choice, and providers generally aim to present the options rather than steer you toward one.
What Research Shows About CVS
CVS involves taking a small sample of placental tissue (chorionic villi), which shares the same genetic origin as the fetus, to test for chromosomal conditions such as Down syndrome, as well as certain genetic disorders when there’s a known family history. According to the American College of Obstetricians and Gynecologists, CVS is typically performed between 10 and 13 weeks of pregnancy, earlier than amniocentesis, which is usually done after 15 weeks. This earlier timing is one reason some women choose CVS over amniocentesis, particularly if they want information sooner in the pregnancy.
How the Procedure Is Performed
CVS can be performed one of two ways: transcervically, where a thin catheter is passed through the cervix, or transabdominally, where a needle is inserted through the abdomen, similar to amniocentesis. The approach used often depends on the position of the placenta and your provider’s assessment of which method offers the safest access. Both approaches are typically done under ultrasound guidance to help the provider visualize the placenta and avoid the fetus.
Many women describe the procedure as uncomfortable rather than severely painful, with sensations similar to menstrual cramping. The procedure itself is brief, though your provider may recommend some rest afterward and monitoring for any unusual symptoms.
Understanding the Risks Involved
Like amniocentesis, CVS carries a small risk of complications, including miscarriage. Research cited by ACOG suggests the procedure-related pregnancy loss risk associated with CVS is low, generally estimated at well under 1%, though this can vary depending on the experience of the provider performing the procedure and individual pregnancy factors. This risk is one of the key considerations that leads some women to choose non-invasive prenatal testing (NIPT) as a screening step first, reserving CVS or amniocentesis for situations where NIPT results suggest further evaluation is warranted.
Women navigating decisions about chromosomal testing results after 35, whether from IVF embryo testing or prenatal screening, often find it helpful to discuss the full landscape of testing options—screening versus diagnostic, timing, and accuracy—with a genetic counselor before deciding on any specific test.
CVS Versus Other Testing Options
Unlike NIPT, which screens cell-free fetal DNA in the mother’s blood and estimates probability, CVS is a diagnostic test that provides a more definitive answer about chromosomal status. This distinction matters: a screening test like NIPT can indicate increased likelihood of a condition, but typically requires a diagnostic test like CVS or amniocentesis for confirmation. Some women choose to go directly to CVS if they have specific risk factors, family history, or simply prefer the certainty of diagnostic testing, while others prefer to start with non-invasive screening and reserve CVS for situations where results indicate a need for further testing.
Providers generally discuss both preconception health factors and prenatal testing options at early appointments, giving you time to research and ask questions before the CVS testing window (typically 10-13 weeks) arrives.
Preparing for the Decision
If you’re weighing whether to have CVS, it can help to think through what you would do with different possible results, how the small procedural risk factors into your comfort level, and whether earlier information (via CVS) or a slightly later timeline with less risk (via amniocentesis) matters more to you. A genetic counselor can walk through your specific risk factors, including maternal age, family history, and any prior screening results, to help you weigh these options.
Emotional Aspects of Diagnostic Testing Decisions
Beyond the medical logistics, deciding whether to pursue CVS often carries emotional weight that’s worth acknowledging. Some women feel that having definitive information as early as possible helps them prepare, regardless of the outcome, while others prefer to avoid procedures with any miscarriage risk and are willing to wait longer for information or to forgo diagnostic testing altogether if screening results are reassuring. Neither approach reflects more or less care about the pregnancy—they simply reflect different ways of managing uncertainty.
If you’re undecided, it can help to talk through the decision with your partner, a genetic counselor, or a trusted friend who won’t pressure you toward a particular choice. Some women also find it useful to write down their specific concerns and questions ahead of an appointment, since decision fatigue and the emotional intensity of early pregnancy can make it easy to forget questions in the moment.
Frequently Asked Questions
Is CVS more accurate than NIPT?
CVS is a diagnostic test and generally provides more definitive results for chromosomal conditions than NIPT, which is a screening test that estimates probability. However, NIPT is non-invasive and carries no procedural risk, which is why many providers use it as a first step.
How soon after CVS will I get results?
Timing varies by lab and the specific tests ordered, but preliminary results are often available within a few days to two weeks, with more comprehensive results sometimes taking longer. Your provider or genetic counselor can give you a timeline specific to your testing panel.
Can CVS detect all genetic conditions?
No test detects every possible genetic or chromosomal condition. CVS is generally used to test for specific conditions based on your risk factors, family history, or requested panel, so it’s worth discussing with a genetic counselor what is and isn’t included in your specific testing.
Is CVS recommended for all pregnant women over 35?
CVS is offered to women of all ages who want diagnostic testing, and age alone doesn’t mandate the procedure. Many women over 35 choose non-invasive screening first and pursue diagnostic testing only if indicated, while others prefer diagnostic testing directly. This is a personal decision made with your provider.
What happens if CVS results show a chromosomal condition?
If results indicate a chromosomal condition, your care team, often including a genetic counselor and maternal-fetal medicine specialist, will discuss what the specific finding means, what additional information or testing may be available, and the range of options available to you going forward.
Key Takeaways
- CVS is a diagnostic prenatal test performed between 10-13 weeks, testing placental tissue for chromosomal and certain genetic conditions.
- The procedure carries a small risk of miscarriage, generally cited as well under 1%, which factors into many women’s decision-making.
- CVS offers earlier results than amniocentesis but carries similar general risk considerations.
- NIPT is a non-invasive screening alternative that many women use first, reserving diagnostic testing for situations where it’s indicated.
- A genetic counselor can help you weigh your specific risk factors and personal preferences when deciding between testing options.
Medical Disclaimer
This content is for informational purposes only and does not constitute medical advice. Individual health situations vary significantly. Always consult a qualified healthcare provider before making decisions related to your health, fertility, or pregnancy.
About the Author
Emily Carter is a women’s health writer focused on fertility, pregnancy after 35, and sleep changes in midlife. She writes research-informed, non-alarmist content to help women navigate reproductive and hormonal transitions with clarity and confidence.