Placental biopsy

 

During pregnancy, it is possible, under certain restrictions, to perform tests to check that the baby is healthy and normal. This is most frequently performed in the form of Ultrasound, but there are other more specialized interventions which may sometimes be required in order to detect abnormalities. These are discussed on this page.

  

Pre-natal  diagnosis procedures are recommended to all couples with a family history of hereditary defects, if the woman is over the age of 35, or if they have had IVF-ICSI treatment. IVF nowadays a trusted technique, but ICSI is still relatively new and much more data needs to be collected regarding the results of this procedure, in order to assess its long term effects. There are however up to this point in time, no indications that ICSI is unsafe in any way, shape or form.

  

Ultrasound scans are a standard procedure in the monitoring of pregnancy. But they are also used to detect any malformations of the foetus.

The safe and painless examination works by projecting high frequency sound waves through the abdomen, in order to produce an image of the foetus and placenta on a monitor. It is best performed with a full bladder. 

   

In order to detect Downs Syndrome, it is necessary to perform either a placental biopsy, an amniocentesis or a chord puncture. An initial blood test will establish whether there is an increased risk. If there is, one of the previously mentioned tests will confirm whether or not the condition is present in the child.

The blood test is only an indication and not concrete proof. It may deliver a negative result, even if the child does have Downs.

  
Placental biopsy

This test involves the removal of a small amount of placental tissue between the tenth and twelfth week of pregnancy. Under ultrasound guidance via the vagina, a narrow tube is inserted into the placenta and a small biopsy is taken. The results of the test are known two weeks later.

    
Amniocentesis

This is performed around the fourteenth week of pregnancy. A needle is inserted through the abdomen and a small amount of amniotic fluid is aspirated. Both the fluid and the cells from the baby which it contains are examined. Usually, the results of this test are available four weeks later.

Considered choice
The Placental biopsy can be performed earlier than the amniocentesis, but the chance of triggering a miscarriage is twice as high: 1% as opposed to 0.5%. Which test to perform is decided individually. The opinion of the doctor and that of the couple are both taken into account. In general, a placental biopsy is preferred in twin pregnancy and an amniocentesis in singleton pregnancies.

  

Occasionally, umbilical cord puncture is performed as an alternative to the methods mentioned above. This involves taking a blood sample from the umbilical cord. The procedure is performed mostly in the eighteenth week of pregnancy.

The test is performed if ultrasound indicated a malformation of the foetus, in order to determine whether this is a hereditary abnormality.

The test is also performed in women who have passed the eighteenth week of pregnancy, but who require a pre-natal diagnosis.