(CVS)
Chorion Villus Sampling
Chorion villus sampling (CVS) obtains a sample from the placenta (chorionic villi. Both the baby and placenta (afterbirth) originate from the same cell and so the chromosomes present in the cells of the placenta are usually the same as those of the baby.
CVS is an invasive procedure used to diagnose chromosomal abnormalities, like Down’s Syndrome. It can also be used to detect various genetic syndromes e.g. Cystic Fibrosis. It is performed under ultrasound guidance between 11 and 15 weeks of pregnancy.
A fine needle is passed through the tummy and into the womb so that a sample of placental tissue can be obtained.
The sample is sent to the laboratory for chromosome analysis and the rapid result is available within 48-72 working hours. A more detailed genetic testing is usually available two weeks after CVS. As the procedure involves putting a needle into the womb, it carries a small risk (around 0.5-1%) of miscarriage. CVS lasts 1 minute and afterwards we check that the baby’s heart beat is normal. Some women might experience mild abdominal pain or period-like pain. In this case, you may find it helpful to take simple pain killers like paracetamol.
Invasive Procedure
Amniocentesis
Amniocentesis obtains a sample of amniotic fluid (fluid around the baby), in order to examine the cells. The cells in the amniotic fluid originate from the baby and so the chromosomes present in these cells are the same as those of the baby. The amniotic fluid is the baby’s urine and the amount removed by amniocentesis reaccumulates within a few hours.
A fine needle is passed through the tummy and into the womb so that a small sample of fluid from around the baby can be obtained. The fluid is sent to the laboratory for chromosome analysis and the rapid result is available within 48-72 working hours. A more detailed genetic testing is usually available two weeks after amniocentesis. As the procedure involves putting a needle into the womb, it carries a small risk (around 0.5-1%) of miscarriage. Amniocentesis lasts 1 minute and afterwards we check that the baby’s heart beat is normal. Some women might experience mild abdominal pain or period-like pain. In this case, you may find it helpful to take simple pain killers like paracetamol.
