Ultrasound Scanning Services | 3D / 4D | Invasive Test
Invasive Tests
Chorion villus sampling at 11-14 weeks
CVS involves the examination of chorionic villi (placental tissue). Both the baby and placenta (afterbirth) develop from the same cell therefore the chromosomes present in the cells of the placenta are the same as those of the baby.
A local anaesthetic is given. A fine needle is then passed through the abdomen and a sample of villi is taken. The procedure lasts 1-2 minutes and is performed under scan guidance. CVS is not performed before 11 weeks. A preliminary result is available in 3 days and the final result within 2-3 weeks.
Amniocentesis
Amniocentesis is not performed before 15 weeks. The procedure lasts 1-2 minutes and is performed under scan guidance. A fine needle is passed through the abdomen and amniotic Fluid around the baby is taken and tested for abnormalities. A preliminary result is available in 3 days and the final result within 2-3 weeks.
Risks
The risk of miscarriage due to CVS and Amniocentesis is about 1% In approximately 1:1000 cases the test will need to be repeated because the results are inconclusive. If you were to miscarry due to the test, this would happen within the next five days. Some studies have shown that when CVS is performed before 10 weeks there is a small risk of abnormality in the baby’s fingers and/or toes. To avoid this risk we never perform CVS before 11 weeks
