Prenatal Tests – Chorionic Villus Sampling vs. Amniocentesis


If you are expecting parents, who have a higher risk of having your baby with any anomalies or other health conditions, you may consider going for these prenatal tests – Chorionic Villus Sampling (CVS) or Amniocentesis. These tests help in determining genetic disorders or birth related issues of the growing fetus.

The information from the test results help the parents in knowing about the condition beforehand and allows them to take crucial decisions. You can choose to go for these invasive tests, if you or your partner’s family has a history of any of the rare conditions or if your recent ultrasound or screening test results showed to be abnormal.

Prenatal Tests

Chorionic villus sampling (CVS)

This test requires collecting small amount of placental cells from the uterus. These cells are known to contain the genetic information, same as that of the fetus and if anomalies are found in these cells, then the baby is said to be having them too.

  • This test can be performed as early as 11 weeks.
  • In case of transabdominal CVS procedure, a surgical needle is inserted through the abdomen, into the uterus to collect the sample, with the help of ultrasound as a guide.
  • In case of transcervical CVS procedure, a needle is placed into the cervix and into the uterus with the help of ultrasound as guide and a sample of the cells is collected.
  • CVS helps in identifying Down syndrome or other conditions such as cystic fibrosis.
  • This test cannot identify neural tube conditions or Rh incompatibility.


This test involves collecting a sample of amniotic fluid surrounded the baby in the womb and getting it evaluated. Amniotic fluid is known to contain baby’s skin tissues.

  • Amniocentesis procedure involves inserting a surgical needle into the uterus from the abdomen and extracting the fluid. The small amount of fluid drawn will be replaced by the body again.
  • This test can be performed after 15 weeks gestation.
  • This test helps in identifying genetic conditions, neural tube defects and other health issues.

You may feel mild cramping and discomfort during the procedures of the above two tests. You should also consider the risks involved with both the procedures. There are slight chances of –

  • Injury to the baby
  • Damage to the blood vessels or other parts of the mother
  • Miscarriage
  • Preterm labor
  • Vaginal bleeding
  • Leaking of amniotic fluid


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