DNA blood test for Down’s syndrome

Summary of story from BBC News, 12.1.11.

A DNA blood test for Down’s syndrome could save nearly all pregnant women from invasive tests like amniocentesis, experts claim.

Down’s syndrome, a genetic disorder, affects a baby’s normal physical development and causes learning difficulties.

Invasive testing takes place in three to five percent of pregnant women in the UK, around 30,000 women, and increases the risk of miscarriage.

The new DNA blood test could bring this down to 0.1 percent according to a study in the British Medical Journal.

Around one woman in every 100 who has an invasive test will miscarry.

From 2007 to 2008, 1,843 cases of Down’s syndrome were diagnosed during pregnancy in the UK, and 743 babies were born with the lifelong condition.  About one in every 1,000 live births is affected by the condition.

The causes of Down’s syndrome are unclear, but the single biggest risk factor seems to be the age at which a woman gives birth.

The older a woman is when she has a baby, the higher the risk of her baby having Down’s syndrome.  The greatest risk (one in 30) is associated with women aged 45 or over.