CVS and Amniocentesis: What, How, and Why
Testing is at the heart of prenatal genetics. With an accurate approach, prenatal genetic testing can help determine the right care plan for you and your baby. Two of these testing options, CVS and amniocentesis, are two uncommon testing options offered by our award-winning team. On our latest episode of “Healthful Women,” Dr. Nathan Fox meets with MFMA founder and president, Dr. Andrei Rebarber, to discuss what to expect from these tests, how they’re performed, and why you might opt for these testing methods.
What are CVS and Amniocentesis?
Both CVS and Amniocentesis are diagnostic tests which “…in general is a test that is able to diagnose a problem, whereas screening tests suggest risk,” Dr. Rebarber explains. Although diagnostic tests are often more invasive (meaning a tissue sample is required), they can most accurately return a “yes” or “no” response for targeted testing needs. Both tests are options for assessing your baby’s genetic material to determine whether any high-risk conditions are present.
How are CVS and Amniocentesis Performed and What Are the Risks Involved ?
CVS can be performed either transvaginally (using a small catheter rather than a needle) or transabdominally in order to take a sample of the placental tissue. Additionally, amniocentesis is performed transabdominally with the same goal. These are two of the most common options for invasive genetic testing.
The most recent data suggests that both procedures may have slight to no increase in risk of pregnancy loss. In a recent large analysis of multiple studies published in 2019 in a leading obstetrics journal (Salomon et al., Ultrasound in Obstetrics and Gynecology) the procedure-related risk of miscarriage (loss < 24 wks) was 0.3% for amniocentesis with no significant procedure-related risk associated with CVS, which may be a safer procedure. The recent data on twin gestations undergoing these procedures further supports the minute risks of complications these procedures have on the wellbeing of the pregnancy. In fact, in this later study on twins, there is no significant difference in fetal loss when comparing fetal loss before 24 weeks (or within 4 weeks of the procedure) when comparing twin pregnancies who had invasive testing versus those that did not.
Why Would I Undergo Amniocentesis or CVS?
This mostly depends on your unique treatment plan with your Maternal Fetal Medicine Specialist. However, Dr. Fox explains some of the most common reasons that mothers choose invasive genetic testing. “The way they sort of conceptualize… is alright… 25% of having a baby with a certain genetic condition, and you want to test for it. So that’s sort of like one bucket. Another one is, you know, you did some screening, and your risk has increased, and you want to find out, you know, what’s going on. So that’s the second bucket… the third is just, you know, simple reassurance.”
Genetic Testing with Your Maternal Fetal Medicine Specialist
The best way to determine whether you can benefit from CVS and amniocentesis is by discussing your options with a high-risk pregnancy expert, OB/GYN, midwife, or genetic counselor. Patients should be counseled properly about what genetic information they would want, and that can then inform the physicians the type of test that should be sent to the lab.
Schedule an Appointment
At Maternal Fetal Medicine Associates, our award-winning team can support you at every step of your pregnancy journey. To learn more about your genetic testing options, we invite you to schedule an appointment at our New York City office by calling or filling out our online form.
Learn more about prenatal genetics by checking out Healthful Women here.
Maternal Fetal Medicine blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!