A new blood test developed in the US can detect more than 99% of Down's syndrome cases without the risk of miscarriage, it has been claimed.

The non-invasive test could save around 300 babies a year, according to a recent study by researchers in London.

Currently, mothers of a foetus deemed to be at high risk of developing the condition undergo a test called amniocentesis - an invasive procedure that involves sticking a needle into the womb.

One in 100 women who have that test will miscarry.

ITV News' Science and Medical Editor Lawrence McGinty reports:

As part of the new procedure the mother undergoes a blood test, which can be done during her first trimester.

Doctors then test whether the baby's DNA is present in the mother's blood stream - a telltale sign of the syndrome.

  • Around one in 1,000 babies born in the UK will have Down's syndrome

  • In the UK there are 60,000 people with the syndrome

  • The condition is caused by an extra chromosome present in a baby's cells

  • The average life expectancy for a person with Down's syndrome is 50-60

Researchers at the Harris Birthright Research Centre for Foetal Medicine at King’s College Hospital found the method to be extremely accurate.

The study screened 2,049 women who were in their 11th to 13th week of pregnancy.

By examining cell-free DNA in the mother's blood, the researchers were able to successfully detect more than 99% of Down's syndrome cases.

Professor Kypros Nicolaides, who led the study, said the false positive rate - or the number of unnecessary tests done - was just 0.1%.

Down’s Syndrome Association Chief Executive Carol Boys said of the study:

Our aim is that all pregnant women will receive relevant, accurate and up-to-date information about Down’s syndrome, delivered by midwives and associated health professionals, who have received our targeted training prior to any screening test. We are currently seeking full funding to ensure that our training can be rolled out nationally in readiness for the time when the non-invasive diagnostic test in early pregnancy is a reality in the UK.

Though the new test is highly effective, it is also expensive.

When the procedure becomes available in Britain it will likely cost £500 a time, while the machine that conducts the analysis costs £500,000.

The UK National Screening Committee will keep all evidence for pre-natal screening under review and make recommendations in light of any new findings.

The procedure - known as the Harmony Prenatal Test - will be available in private UK clinics within a matter of weeks.

It is already being used in some US clinics after being developed by Ariosa Diagnostics.