21 Oct The Harmony Test (NIPT): should you have it?
Should we have the Harmony test? It’s a question our patients often ask. They’ve read about non-invasive prenatal testing (NIPT) on the pregnancy and fertility forums. And the Harmony test is often mentioned. So here are the key things you need to know about the Harmony test – and NIPT in general. You can then decide if it’s right for you.
The Harmony test, like all NIPTs, is a blood test for pregnant women. It can be done as early as week 10 of your pregnancy. It picks up a marker of the baby’s DNA in maternal blood. That reading, based on cell-free genetic analysis, can give a probability score (not a diagnosis) for at least three chromosomal anomalies in the baby’s genes.
The Harmony test is more than 99% predictive of the risk of Down’s syndrome (trisomy 21). It’s also more than 98% predictive of the risk of Edwards’ syndrome (trisomy 18) and 80% predictive of the risk of Patau’s syndrome (trisomy 13).
Let’s go back a step. For a decade or more, women have been assessed for Down’s syndrome, and other fetal chromosomal problems, via the nuchal translucency scan at 12 weeks. Accompanied by a blood screen, it’s called the ‘combined test’. High-risk patients then need to have a CVS or amniocentesis, both highly invasive tests, to confirm the diagnosis. 1 in 100 of them will miscarry the baby as a result of either test. That’s really rather high.
Little wonder that non-invasive prenatal testing (NIPT), of which the Harmony test is one of several products, came along. It’s expensive: we’ve seen prices of £500 or more in the UK. A scan is routinely included in the price. But for many women, it offers safety and certainty. A low-risk score means you won’t have to undergo that stressful and risky invasive testing. NIPT can also tell you if you’re having a boy or a girl. (Sometimes that’s medically important, not just nice to know.)
But NIPTs aren’t without controversy and ethical debate. Some might argue they encourage a culture of rejection over nurture, in that some pregnant women may view earlier, easier and more accurate testing as a fast-track route to termination. The counter argument is that pregnant women have every right to know the facts, and to make informed choices, about their pregnancies. The Harmony test, like other NIPT products on the market, is a screening test, not a diagnostic one. So a ‘high risk’ or ‘likely to be affected’ result does not confirm things: you still need the amniocentesis or CVS to be sure. False positives after NIPT are still possible.
Will NIPTs be routinely available of the NHS? Hot topic. Research has looked at the medical and economic benefits of a national roll-out of non-invasive prenatal testing. In June 2015, Professor Lyn Chitty presented her findings to the European Society of Human Genetics. There were many positive findings. Ultimately, it will all come down to how much a nationalised NIPT service will cost the NHS.
And bingo. In early 2016, the verdict of the UK National Screening Committee, following a public consultation, was this. High-risk mothers, those with a 1 in 150 chance of having a baby with one of the three conditions, should be offered an NIPT on the NHS. Now we await the government green light. (Note to government: please get on with it.)
For now, and perhaps for only a few months more, NIPTs are only really available privately. Competitors to the Harmony test includes the Panoroma and NIFTY tests. It’s worth checking the published data of test results on each of their websites. For example, the Panorama test appears to have a higher predictive percentage score for Edward’s and Patau’s syndrome than the Harmony test. But Harmony is more sensitive to Turner’s syndrome (monosomy X) than Panoroma and it’s also available for twins and donor-egg pregnancies.
There are many good things about non-invasive prenatal testing. For older women, where the chances of a chromosomal abnormality are higher, it may be sensible. These might include fertility patients in their late 30s or 40s who have IVF with their own eggs. Or women who’ve had a past chromosomal issue. Or women who just want to know.
As for the future, we predict that non-invasive prenatal testing will be available to all pregnant women in the UK by 2017. As for the rest of the world, we shall wait and see.