Chorionic Villus Sampling, PDF

What Is Chorionic Villus Sampling?

Chorionic villus sampling (CVS) is a prenatal diagnostic test performed by obtaining a small sample of cells or tissues from the placenta called chorionic villi under the guidance of ultrasound to identify if there are any birth defects, genetic diseases, or other issues during the pregnancy. This sampling technique has two options: using a needle for transabdominal CVS (TA-CVS) or using a specialized catheter for transcervical CVS (TC-CVS). Obstetricians and gynecologists recommend their patients undergo CVS if they are over 35 years old, have a previously affected child, have a family history of a certain genetic disease, or have a previous ultrasound with abnormal findings.

According to a Mayo Clinic report, 0.22% is the estimated rate of the risk of miscarriage in pregnant women who took CVS and another study revealed that approximately 150,000 women found that CVS was not linked at all with a risk of miscarriage. Additionally, there is a very small percentage—nearly 1% chance of a false positive with CVS. If you are planning to have a CVS procedure, consult your obstetrician, gynecologist, or healthcare provider concerning the potential risks from this test and their specific miscarriage rates. 

Advantages of Chorionic Villus Sampling

If you are 35 or older on your due date, have a family history of a genetic condition, or if your partner does, most doctors and healthcare providers may offer you to take chorionic villus sampling. What are the notable benefits of chorionic sampling based on clinical evaluation reports?

Guides in Proper Decision-Making in Managing Pregnancy: How essential is this prenatal test for you? Why are you doing this procedure? If you get a definite answer, does that mean you want to terminate the pregnancy or continue with the pregnancy and move forward whatever the case may be? Consider your major goals and objectives in taking CVS. This sampling method helps you to contemplate your case and guides you to formulate proper decisions on what is best for your pregnancy and your unborn child. Performing CVS and confirming its diagnosis helps you to pursue possible interventions that may arrive, start planning for a child with special needs, begin addressing anticipated lifestyle changes, identify support groups based on your case, and create a firm decision about carrying the child to term. Obtains Accurate Genetic Information of the Baby: Chorionic villus sampling is a comprehensive prenatal biopsy test in which it examines the genetics of cells in the placental villi so that it can obtain an accurate and extensive range of genetic disorders. Due to the latest medical technological advancements in genetic knowledge and qualitative data analysis, CVS can easily collect vital genetic information, even small genetic changes from the baby inside the mother’s womb. Detects Potential Birth Defects and Other Diseases: Do you need to further know and understand the condition of your unborn baby? CVS is a beneficial sampling technique that lets your doctor detects potential birth defects and other genetic diseases and informs you if your baby is more likely than others to acquire certain health conditions or chromosomal abnormalities such as Cystic fibrosis, Down syndrome, Sickle cell disease, Tay-Sachs disease, and Trisomy 18 or Edward syndrome. Thus, you can depend on CVS test results because of the test’s high accuracy. Timing: As this prenatal test is typically performed during the early trimester of pregnancy, expecting mothers have more time to conduct in-depth research and formulate crucial decisions on their pregnancy.

Risks and Side Effects of Chorionic Villus Sampling

Despite having notable benefits, chorionic villus sampling also has its possible risks and side effects for the patients. These risks may differ from one individual to another. Mostly, some pregnant women experience less to no risks or side effects from taking their CVS procedures. Use a health and safety checklist to determine if you are at risk of this test.

1. Not Recommended for Women with Certain Conditions

Women who have an active infection like STD, pregnant women who are carrying twins, and those who have experienced vaginal bleeding during pregnancy are not recommended to take CVS. Also, women who have uterine fibroids and have a tilted uterus which impedes the catheter are not recommended to take transcervical CVS. 

2. Miscarriage and Infections

The miscarriage risk with CVS is about 1 in 300-500. If you are an expecting mom, CVS can cause miscarriage or the loss of pregnancy in the first 23 weeks. Most miscarriages that occur after CVS take place within 3 days of the test. However, several case studies revealed that the chance of miscarrying after CVS is less than 1 in 200 for most pregnancies and nearly 1 in 100 for multiple pregnancies like having twins or triplets.

3. Insufficient Chorionic Villi Sample

Typically, the chorionic villi or the sample of placental cells or tissues collected in around 1 in 100 CVS procedures may not be suitable for testing. In some cases, this is due to insufficient placental cells or tissues being taken. While other cases are not performed properly because the chorionic villus sample was contaminated with the cells from the mother. If the sample is inappropriate, the CVS test should be performed again, or the patient could wait for a few weeks to get amniocentesis instead.

4. Rhesus Sensitization

Rhesus or RhD sensitization is a condition where some of your unborn baby’s blood enters your bloodstream, and your body begins to create antibodies to attack it which can lead to the baby developing the Rhesus disease if left untreated. You must take a blood test before the CVS test if you are not aware of your blood type. To stop Rhesus sensitization from occurring, a medicated injection called anti-D immunoglobulin must be given. 

How to Conduct Chorionic Villus Sampling

Medical professionals who specialized in obstetrics, gynecology, child development, and genetics stated from their research studies and expertise that chorionic villus sampling is considered to be 98% accurate in the diagnosis of chromosomal defects. What are the steps used by the doctors to conduct a CVS test?

Step 1: Genetic Counseling

Consult with your doctor about your current condition and have a detailed discussion on the benefits, risks, and side effects of the CVS procedure. Then, you will have a whole abdomen ultrasound exam on your initial consultation and genetic counseling to confirm the gestational age and the location of the placenta so that CVS can be done at the right and safe gestational age, usually around 10 to 12 weeks from the woman’s last menstrual period.

Step 2: Chorionic Villi or Placental Cell Collection

Your doctor can use two methods to conduct a CVS prenatal test: transabdominal chorionic villus sampling (TA-CVS) and transvaginal chorionic villus sampling (TV-CVS). A transabdominal chorionic villus sampling (TA-CVS) test is done via your abdomen as your doctor will use an ultrasound to guide a long, thin needle through your abdominal wall and into your uterus to extract the tissue sample. The method that will be carried out depends on the location of the placenta and the position of your uterus.

Step 3: CVS Sample Lab Analysis

After the placental cell collection, the chorionic villi sample will be delivered to a laboratory where the pathologist will grow the cells in a special fluid and be tested a few days later. The results of the CVS sample culture will be available within 2 weeks.

Step 4: Result of the CVS Test

Wait for the doctor to notify you of the CVS test results. Visit your doctor’s clinic immediately when you are notified. If you have a concern or issue, ask a genetic counselor and discuss your options.

FAQs

How accurate is the CVS pregnancy test?

The CVS pregnancy test gives accurate and precise results in 99 out of every 100 pregnant women having the CVS procedure. It can also determine the sex or gender of the fetus to detect potential disorders that are linked to one sex. 

Which is safer CVS or amniocentesis?

Medical researchers and scientific authors concluded in their studies that amniocentesis done in the second trimester is safer than amniocentesis or transcervical CVS performed in the first trimester. When testing is conducted before 15 weeks gestation, transabdominal CVS must be highly considered.

What to expect after a chorionic villus sampling procedure?

You may possibly go home in 15 to 30 minutes after you undergo a chorionic villus sampling procedure. Your healthcare provider or medical specialist may advise you to avoid strenuous workouts like lifting heavy objects and also avoid sex. Also, you may notice some cramping or vaginal spotting.

What is the difference between amniocentesis and chorionic villus sampling?

Amniocentesis is a prenatal procedure in which a needle is inserted through the abdomen into the uterus to take an amniotic fluid sample. This test can be performed before 15 weeks. While chorionic villus sampling is a prenatal sampling method in which a needle is used to withdraw a placental tissue sample.

How long does a chorionic villus sampling take to recover?

Some pregnant women who take chorionic villus sampling can return to their daily activities within 24 hours. Almost 25% of patients who have had transcervical chorionic villus sampling will experience some spotting or vaginal bleeding after the medical procedure and those who underwent transabdominal chorionic villus sampling have had less to no amount of bleeding.

Chorionic villus sampling is an accurate and effective prenatal test to identify potential birth defects and genetic diseases of your unborn baby. It helps you to make proper decisions, to understand the condition of your baby, and to check on what options you need to do after you are notified of the result of the CVS test. Sample.net provides a wide selection of PDF templates for chorionic villus sampling, purposive sampling, cluster sampling, systematic sampling, and other sampling methods that medical professionals and researchers can download and use with ease and comfort while working on their labor and delivery assessments and research studies.