Fears babies at risk
North Coast Radiography sonographer Mark Bryant is pushing for a review of the ultrasound tests, called Nuchal Translucency, which he says can be completely inaccurate.
His fears are backed by British expert in radiology Dr Hylton Meire, who has said the unreliable Nuchal tests often lead to women needlessly undergoing a round of invasive tests that can lead to miscarriage.
The claims have concerned Lismore parents-to-be Alix Madden and Shane Dimaio, who told The Northern Star the test shouldn't be done at all if it means giving expectant mums inaccurate information.
"It's scary," Ms Madden said.
"If the tests don't work properly they should find a way of doing them better, or maybe not do them at all."
But Sydney Ultrasound's Dr Andrew McLennan has slammed the claims, saying the test, which is rigorously audited, has actually reduced the rate of invasive tests being performed on pregnant women.
Nuchal tests, done at about 12 weeks into the pregnancy, measure the fluid at the back of the foetus's neck and this, together with maternal age, is calculated to give an individual risk of Down's syndrome.
Parents use this score to decide whether to have a test called an amniocentesis, which involves taking a sample of fluid from the womb.
The test determines if the baby does have Down's, but carries about a one-in-200 risk of causing a miscarriage.
Ms Madden, whose baby girl is due on June 22, had the Nuchal test done and was told her baby had a low risk of being born with Down's syndrome.
She said having the test and waiting for the result was scary enough, but she could't imagine what it would be like if an expectant mum was given an incorrect rating. "It's not fair on the parents," she said.
Mr Bryant has written a paper on the inaccuracy of the Nuchal tests, which is being reviewed by the UK National Screening Committee, along with another paper on the same issue by Professor of Medical Physics at Leeds University in the UK, Tony Evans.
He said the results of a Nuchal test could change by up to 100 per cent, depending on how much frequency was used in the ultrasound and how much the image was enlarged.
Mr Bryant first raised the issue two years ago, but at that time no one else had ever questioned the physics behind the Nuchal tests and he was shouted down, he said.
"The idea of the scans at 12 weeks is good, we just need to smarten up the NT test," he said.