Chorionic Villus Sampling

Chorionic villus sampling is tests which are done to check if the foetus is suffering from any serious problems. Pregnant women who are above the age of 35 or who have family history of heredity disorders are subjected to chorionic villus sampling. This is used as an alternative for amniocentesis. In amniocentesis, the test is performed by taking a sample of the amniotic fluid form the mother. The advantage of doing a chorionic villus sampling is that it can be done around ten weeks of gestation. The time taken for a chorionic villus sampling is only 20 minutes.

The chorionic villi that are finger like projections from the placenta formed by the fertilised egg division. So the genetic code of the villi will be the same as the embryo. Hence a chorionic villus sampling will help to detect any abnormality that can be present in the baby.

But in certain cases, chorionic villus sampling can result in miscarriage.

Necessity of Chorionic Villus Sampling

Chorionic villus sampling helps in to diagnose the presence of severe genetic disorders in babies. If the disorder that has been diagnosed cannot be rectified or if it can damage the health of the baby, the parents may terminate pregnancy. Chorionic villus sampling also helps the parents to be mentally prepared for the problems they may have to face in the future.

Many disorders that may be present in the foetu8s can be diagnosed using chorionic villus sampling. They are:

• Cystic fibrosis
• Down’s syndrome
• any chromosomal disorder
• musculoskeletal system like Duchenne muscular dystrophy
• sickle cell anaemia
• blood related disorders
• thalassaemia
• antitrypsin deficiency
• phenylketonuria
• other metabolic disorders
• Fragile X syndrome
• mental health problems if any

When should it be performed

Chorionic villus sampling can be done at the tenth week or after ten weeks of gestation. Usually it is done earlier, but there is high risk associated with miscarriage during a chorionic villus sampling.

Even though amniocentesis is a good alternative, which can be done around fifteen to twenty weeks of pregnancy, it will be difficult if the person wants to terminate the pregnancy, in case if any incurable condition is diagnosed.

The mothers of babies who have higher chances of developing inherited disorders are advised to undergo chorionic villus sampling. If a woman had experienced severe problems in her previous pregnancy, the woman is asked to undergo this test.

Pregnant women above the age of thirty five are also advised to undergo Chorionic villus sampling as there is high risk of the baby having Down’s syndrome.

In certain cases, the babies may develop condition like cystic fibrosis, which will be inherited from the family. So if there is the family history associated with such disorders, the pregnant woman must do chorionic villus sampling.

Risks

The risks associated with chorionic villus sampling include:

• possibility of infection from the procedure
• heavy bleeding after performing chorionic villus sampling
• Induced miscarriage in cases of Chorionic villus sampling up to twenty four weeks.
• rhesus sensitisation due to the entering of baby’s blood into the mother’s bloodstream.
• damage to baby like absence of fingers or toes.

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