By Kent Atkinson of NZPA
Wellington, Nov 8 NZPA - New Zealand may get a national screening programme for Down syndrome birth defects next year -- four years after health officials were told some of the present testing is not safe enough.
But political sensitivities continue to dog the project and officials have suggested calling it a "quality improvement" rather than a national screening programme, according to a senior academic.
The Health Ministry's antenatal screening unit called in 2007 for changes to improve antenatal screening for Down syndrome.
As well as sensitivities around abortion and eugenics -- aborting foetuses with disabilities before birth -- a cultural issue has to be overcome.
The proposed effective screening method is to combine blood tests with an ultrasound exam -- a "nuchal translucency (NT) test" to measure the thickness of the back of the neck of the foetus -- in the first 13 weeks of pregnancy, the first trimester.
"Unfortunately a large number of women in New Zealand still present to a health carer for the first time later than this," Peter Stone, professor of maternal foetal medicine at Auckland University, told NZPA.
"This is a socio-cultural issue."
That was a major reason why doctors continued to offer second trimester serum testing.
The NT testing is reported to be more than 80 percent accurate, with a low risk of falsely indicating Down syndrome in a healthy foetus, and women can be given numerical odds of their carrying an affected baby.
A woman determined to be at high risk by the NT test then still has time for an invasive test to tell for sure.
The ministry's advisory group which canvassed a national screening programme in 2007 reached a consensus that New Zealand's approach to screening was unsafe. Prof Stone had already told the unit in February 2006 that the current system should stop.
He suggested that "more normal pregnancies may be adversely affected by amniocentesis than the numbers of Down syndrome foetuses detected".
At least 3500 diagnostic tests with a risk of miscarriage are performed each year, including amniocentesis -- removal of a sample of amniotic fluid for analysis -- and removal of placental tissue for analysis.
The ministry unit previously noted the screening methods being commonly used result in too many women having diagnostic tests, with a risk of about 1 percent to 2 percent of pregnancies being lost unnecessarily.
Prof Stone told NZPA he was still working with the unit trying to sort out a safer and more reliable form of screening but progress had been slow.
"There has been little wide debate because it has been difficult to engage those most affected... the currently or soon-to-be pregnant mothers and, of course, their partners."
Consultation and advice sought by the screening unit and "various changes which appear to be ongoing in the Ministry of Health and in the national screening unit have led to delays".
A ministry spokeswoman said public funding had been provided for second trimester blood tests last year, and from February 2010 funding would be provided for first trimester combined screening -- the combined result from an NT scan and maternal blood tests.
Prof Stone said the eventual screening could provide a platform to assess the "health" of the pregnancy and the baby early on, by including not only Down syndrome but other conditions that could place the woman at higher risk of pre-eclampsia or foetal growth restriction.
But, so far, the only change in the past two years had been the funding for second trimester blood tests -- which was reinstating access that had previously been removed.
Next year he hoped to see the funding and introduction of first trimester blood tests combined with the NT scan to give a combined risk estimate.
"At that point, NT alone will no longer be recommended to be done in isolation from first trimester blood testing," Prof Stone said.
"There will in effect be national screening but due to complex sensitive political factors the advice from the national screening unit and the Director General of Health to the past and current Ministers of Health was not to call this a national screening programme but `quality improvement'."
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