Chorionic Villus Biopsy: A Precise Prenatal Diagnostic Technique

The placenta, a vital organ during pregnancy, not only sustains the growing fetus but also influences maternal physiology. Anomalies in the placenta can signal issues in the developing fetus. Chorionic villus biopsy, an invasive procedure, is a highly accurate method to assess fetal health.

1. Understanding Chorionic Villus Biopsy

Chorionic Villus Sampling (CVS), a technique in obstetrics, involves extracting cells from the chorionic membrane enveloping the embryo. These cells, known as chorionic villi, are then analyzed to identify chromosomal abnormalities, including conditions like Down syndrome (trisomy 21) in the fetus.

2. Indications for Chorionic Villus Biopsy

Chorionic villus biopsy is not recommended for all pregnant individuals. It is typically advised when:

• Other diagnostic tests, such as ultrasound or non-invasive screening tests (NIPT), indicate a risk of Down syndrome or other chromosomal abnormalities.
• Both partners carry recessive genetic disorders, like cystic fibrosis or sickle cell anemia.
• Either the mother or father has specific genetic disorders, such as Thalassemia.
• A previous pregnancy resulted in a child with a genetic abnormality, increasing the risk of recurrence.
• A family history of birth defects is present in either the mother's or father's family.
• Ultrasound examinations detect fetal anomalies like cleft lip and palate, heart defects, kidney abnormalities, or dilated ventricles.

3. Chorionic Villus Biopsy Procedure

During a chorionic villus biopsy, a small placental tissue sample is extracted from the mother's uterus using a needle or catheter through the abdomen. The procedure is performed under anesthesia to minimize discomfort and stress. Afterward, some mild vaginal bleeding may occur. The risk of miscarriage associated with this procedure is approximately 1 in 500, meaning that for every 500 women who undergo it, one might experience a miscarriage. Pregnant individuals are counseled on the advantages and disadvantages of prenatal diagnostic tests before undergoing them.

4. Optimal Timing for Chorionic Villus Biopsy

Chorionic villus biopsy is typically conducted between 12 to 14 weeks of pregnancy, when the placenta is favorably positioned and before the amniotic sac fills the uterine cavity.

Post-Biopsy Considerations:

• After the procedure, pregnant individuals can return home but should refrain from heavy labor and sexual activity for 3 to 4 days.
• In the event of amniotic fluid leakage, vaginal bleeding, or increasing cramps, immediate medical attention is necessary due to the risk of miscarriage.
• Monitoring body temperature after the procedure is essential; the appearance of a fever may indicate infection and requires prompt medical evaluation.
• Chromosomal analysis results are typically available within 7-10 days, while genetic disorder results may take 2-4 weeks. Any questions or concerns about the test results should be addressed with a healthcare professional.

Chorionic villus biopsy serves as a valuable tool in assessing fetal health, especially when there are concerns about genetic or chromosomal abnormalities. It is essential to consult with a healthcare provider to make informed decisions during pregnancy.