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An Italian research has warned that prenatal screenings do not detect chromosomal abnormalities. Study experts told European genetics conference that women need to be more aware of the limitations of such screening tests.

A common example of a chromosomal abnormality is Down's syndrome. In this condition, the fetus has an extra copy of one of the chromosomes. This results in babies with developmental problems, cardiacdefine defects and a distinctive facial appearance.

Amniocentesis confirms the Down's syndrome. Here, a needle is used to take a sample of the fluid within the womb. This test is not normally offered to all pregnant women in the UK but is useful in revealing other birth defects like Edward's syndrome and Patau syndrome.

There are evidences that this test, which uses the fluid around the baby as sample, can cause miscarriage. As a result, roughly 1 in 100 women will miscarry due to the test.