A new non-invasive test to screen foetuses for Down Syndrome is now available in Singapore.

Previously, doctors had to insert a needle into the mother and draw fluids surrounding the baby to test them for indicators of Down Syndrome. This process, called amniocentesis, carries "a small risk of miscarriage".

A new test, called the Non-Invasive Prenatal Test (NIPT) eliminates that risk. Doctors just need to test a sample of the mother's blood for signs of Down Syndrome in the foetus.

Doctors, attending an international medical conference in Singapore on Sunday, however caution that results from the new test must be interpreted with caution. NIPT detects Down Syndrome about 99.5 per cent of the time, but only one in five cases which test positive actually turn out to be real cases, noted adjunct professor George Yeo, chief of obstetrics and gynaecology at KK Women's and Children's Hospital (KKH). Women still need to go for amniocentesis to determine if indeed their baby has Down Syndrome.

"NIPT is a good first level test, but mothers should not be making decisions based on that information alone. Or else they might be terminating pregnancies that are perfectly fine," he said of the new test.

The test, which costs $2,000, should only be taken if mothers are classified as high-risk in first-level screening tests. This about 5 per cent of all pregnant mothers. The unsubsidised test was available in KKH and SGH since late last year.

So far, 43 women have taken the NIPT in KKH and SGH. All have tested negative. The test saved them the pain of having a needle injected into their belly for amniocentesis, noted doctors.

Doctors also reminded women to go for first trimester screening which is costs about $200 after government subsidies. This screening picks up indicators of Down Syndrome and structural abnormalities. It can only be done in the 11th to 13th week of pregnancy. Women should go to their doctors early to avoid missing this window for first trimester screening, Prof Tan said.