A calculated risk... but normally for the child
The risks from amniocentesis are usually thought to affect only the unborn baby.
The devastating outcome in the case of Jane McCarthy has happened just once before, even though up to 40,000 tests are carried out each year. It is an invasive test to detect Down's syndrome or other chromosomal abnormalities.
Doctors normally say the risk of miscarriage is between one in 100 and 200. It is usually carried out 16-20 weeks into pregnancy but can be done later.
A fine needle is inserted into the womb and a sample of amniotic fluid - the liquid around the baby - is removed.
The fluid contains cells from the baby which show whether or not it has an extra chromosome, signalling Down's syndrome.
The rare complication of the needle perforating the bowel or nicking the amniotic sac, which contains the amniotic fluid, would provide a gateway for toxins in the bowel to enter the mother's blood.
Professor David James, an expert in feto-maternal medicine at Queen's Medical Centre, Nottingham, said he had never heard of a mother dying as a result of an amniocentesis test.
He said: 'This is an exceptionally rare occurrence.'
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