Prenatal Genetic Screening

Safe and secure diagnostic screening procedures to detect genetic abnormalities in the unborn child.

About This Information

This information is presented for you if you are pregnant and considering having a chorionic villus sampling (CVS) or an Amniocentesis (‘amnio’). It aims to help you work with your healthcare team to make the best decisions about your care.

Chorionic Villus Sampling:

Chorionic Villus Sampling( CVS), is done at 10-12 weeks of pregnancy.

Why Should One Consider Cvs?

You may wish to consider CVS:

If you have been identified as at high risk of having a child with a genetic disorder
If you have had a high risk result from routine screening (combined screening, double and/or nuchal translucency screening).
Previous child affected with a condition. Example: Thalassemia
The final decision about having any test in pregnancy is yours.

How Is Cvs Performed?

CVS involves taking a tiny amount of the developing placenta, where it is attached to the uterus. The placenta contains tissue that is genetically identical to your baby. CVS may be performed in two ways. Most CVS are performed through the abdomen, but CVS may also be performed through the cervix (neck of the womb). It is performed under an ultrasound guidance to check the positions of both your baby and placenta within the womb.

You would be asked to sign a consent form before the procedure is carried out.

The risk of miscarriage after performing a CVS is 1-2%

How Should I Look After Myself After the Chorionic Villus Sampling Procedure?

Amniocentesis

Amniocentesis is an invasive procedure performed around 16-18 weeks of pregnancy. In amniocentesis a small amount of amniotic fluid – the water around your baby inside your uterus (womb) is taken for testing.

Why Should One Consider Amniocentesis?

You may wish to consider amniocentesis if:

If you have a potential problem found on ultrasound scan, which may suggest chromosomal abnormality
If there is an abnormal result from your regular screening tests
If you have had a previous pregnancy terminated for a genetic condition.
Previous child affected with a genetic condition
Parents being carriers for a condition or one of the parents being affected with a condition

The final decision about having any test in pregnancy is yours.

How Is It Performed?

It is an ultrasound guided procedure. You need to have normal breakfast or lunch before the procedure. Try avoiding coffee and tea, as it leads to more movements of the fetus.

After observing the baby’s movement and position the doctor cleans the abdomen with an antiseptic. Under the guidance of ultrasound a small needle is inserted into the amniotic pocket.

This is to avoid any puncture or damage to the baby. About 20 ml of amniotic fluid is taken out. There is no anesthetic required, you will awake throughout the procedure.

You would be asked to sign a consent form before the procedure is carried out.

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Health problems? Medical Queries? Send us your questions.

Does It Hurt?

The pain from an amniocentesis procedure is similar to having a blood test from your arm, but there would slight cramps or period like pain during the procedure.

What Will the Test Tell Me?

If you are having an amniocentesis for a chromosomal disorder, all chromosomes will be looked at. This means that the test may occasionally detect a problem with the chromosomes which was not expected. If the results show anything abnormal you will be told what the abnormality is and how this will affect your baby. If you are having an amniocentesis for a single gene disorder, only this will be tested for.

The risk of miscarriage after performing a Amniocentesis is 1-2%

PURASAIWALKKAM CENTRE

No. 150, Poonamallee High Road, (Opp to Dasaprakash Hotel) Chennai – 600 084. Tel : 044 43539444