Everything you need to know about NIPT: non-invasive prenatal testing

I got pregnant for the first time at 37, and felt as old as time, with a raisin for a womb and a sky-high risk of having a child with genetic abnormalities. When I unloaded my bag of “geriatric pregnancy” anxiety on my OB/GYN during our eight-week visit, she laughed. Not with me, but notably at me. She told me 37 isn’t that old and, in all likelihood, I would have a healthy pregnancy. But if I was truly concerned about the risks of genetic abnormalities, which do increase with advanced maternal age, I could have a blood test called NIPT, which stands for non-invasive prenatal testing.

Administered at 10 to 13 weeks, and with no physical risk to me or the fetus, NIPT would analyze fragments of placenta DNA that circulate in my bloodstream and screen for extra chromosomes that could indicate Down’s syndrome (trisomy 21), Edwards syndrome (trisomy 18) and Patau syndrome (trisomy 13) with 90 percent accuracy. The traditional set of first-trimester screenings that look for these issues, including the nuchal translucency (NT) ultrasound that measures the thickness of the fluid at the back of the fetus’s neck, have an accuracy rate between 85 and 90 percent and take place between 11 weeks gestation and 14 weeks.

Not only does NIPT offer more precise information earlier, it also has a low false-positive rate: About one in 1,000 people get a false-positive result compared to 50 in 1,000 for the conventional screens. Gathering as much information as early as possible was a deeply comforting idea to my husband and me; as first-time parents, we jittered with worry and excitement in those fledgling weeks. Friends of ours had recently found out the sex of their baby-to-be with the NIPT at only 10 weeks along, and I was eager to know, too.

Pregnant woman holding liquid for glucose testIs the glucose test during pregnancy optional?
But before we got too comfortable, our OB/GYN added a few caveats. NIPT can’t diagnose a disorder; your results simply read “high risk” or “low risk.” Either way, it’s recommended that you follow up with the NT ultrasound and accompanying first-trimester blood test anyhow.

Christine Armour, a medical director for Prenatal Screening Ontario and clinical geneticist at the Children’s Hospital of Eastern Ontario, says NIPT should be seen as a complement to the NT, not a replacement, because the NT gives you information you can’t get from NIPT, like the possibility of congenital heart defects, for example. If we received a high-risk result, we could meet with a genetics expert to discuss what those results mean, the test’s limitations, and next steps. But for an actual diagnosis—because of the reasonable chance of a false positive—we would also need to carry through with chorionic villus sampling (CVS) between 11 and 13 weeks or an amniocentesis between 16 and 20 weeks. Both tests are close to 100 percent accurate, but they carry a 0.5 percent chance of miscarriage and are invasive. (This means they both involve a needle going into your uterus: CVS is a placental sample taken with a needle through your abdomen or with a speculum and tube inserted vaginally; amniocentesis involves a needle that takes a sample of amniotic fluid through the abdomen.) Armed with those results, we could prepare for a child with special needs or consider ending the pregnancy. The idea of “early information” suddenly seemed more like a good first draft that would definitely need some follow-up fact-checking.

And then there was the fact that here in Ontario, where we live, NIPT would cost us anywhere from $600 to $900, because OHIP covers only people who meet the criteria for having a child with a chromosomal difference. The mother must be over 40 at the time of delivery, be carrying an egg from a donor who is over 40, have already received an NT measurement greater than 3.5 millimetres on the NT screening, or have a history of a previous pregnancy or child with a chromosome condition.

Despite my perceived antiquity, I ticked none of those boxes, and my early tests were normal, so my husband and I decided to save our money and do the regular screenings. We waited to find out the sex at the 20-week anatomy scan.

Since NIPT was first introduced in Canada in 2013, the number of women opting for it has shot straight upward. (In 2013, 902 pregnant people in Ontario underwent NIPT, and by 2017, that number jumped to 13,739.) Approximately two-thirds of those were covered by provincial healthcare, while a third paid out of pocket. Ontario and British Columbia were the first provinces to offer coverage to people with high-risk pregnancies, and Manitoba, Prince Edward Island, Yukon, Nova Scotia and Quebec have since joined. (It’s available privately elsewhere in the country.)

In 2017, the Society of Obstetricians and Gynaecologists of Canada and the Canadian College of Medical Geneticists updated their guidelines to include NIPT in the conversations OB/GYNs should have with patients about their prenatal screening options.

“Women tend to like the idea of a test that’s extremely accurate and non-invasive, and people are more aware of it now, because there’s been a large marketing push by the companies that offer it,” says Armour, explaining NIPT’s popularity and referring to its rapidly growing global market. (In China, NIPT is marketed as Bambini, and in India, it’s known as Nifty.)

In Canada, NIPT is mainly offered by two private companies: LifeLabs Genetics, which markets the test under the name Panorama and offers it as early as at nine weeks, and Dynacare, which calls it Harmony. This was one of the most confusing aspects of my research when I was furiously googling NIPT locations in my city. Each website offered a bundle of options and invited me to upgrade my set of prenatal screens like it was a Burger King combo. At LifeLabs Genetics, for example, I could get the basic prenatal panel for $550 or I could pay an extra $245 for the full prenatal panel, which would also screen for missing chromosomes (indicating one of a handful of microdeletion syndromes, which are much more rare).

Stacy Costa, an OB who practises maternal-fetal medicine at Scarborough Health Network, recommends that most patients stick to the three trisomies, for which NIPT is most accurate.

The question Costa gets most often about the screen is “Why won’t the province pay for me to get NIPT?” For those with average-risk pregnancies who find early information soothing, it can feel like peace of mind is available only to people who have an extra $500.

But Health Quality Ontario, the organization that assesses new medical technologies and makes recommendations to the province of Ontario, where Costa practises, studied the benefits of covering the service for all pregnant people, regardless of risk, and ultimately recommended against it. The test, they determined, is expensive and may not be a good use of provincial money in pregnancies with average risk.

It’s something to keep an eye on, though. PEGASUS-2, a Quebec-based Genome Canada project involving researchers from across the country, is working to assess cost effectiveness and further develop NIPT technology that would help make it accessible to all pregnant women in Canada within a few years.

NIPT for all is, of course, an ethically loaded prospect. In the era of mail-order DIY test-kit companies like 23andMe, comprehensive genetic info is becoming a more mainstream part of our culture. But there are also unintended consequences: Down’s syndrome advocacy groups worry that it could lead people to screen the condition out of future generations, and others are concerned it could result in more sex-selective abortions.

Armour cautions that women need to be prepared to deal with all the information they get from the test. “When a woman consents to this, she needs to understand that unanticipated information can come back. For example, you might simply want to know the sex, and the results might come back saying the fetus has an unexpected chromosomal difference, which you might not have wanted to know.”

Information isn’t always an anxiety balm; it can also be a trigger. (That’s why OBs and midwives tend to recommend seeing a genetic counsellor if an NIPT comes back high risk.) It’s also why genetic testing companies who advertise their services to anxious couples and vulnerable pregnant women is becoming a hot topic. In late 2019, the UK banned a series of NIPT ads making false claims about accuracy. Timothy Caulfield (author of Is Gwyneth Paltrow Wrong about Everything?) is currently studying the ethics of NIPT marketing.

Of course we crave certainty in a time of inherent uncertainty—a pregnancy is peppered with question marks and unknowns—but that doesn’t mean expectant parents should feel pressured into paying for an expensive test.

Read more:
Would you invite 50 of your closest friends to your ultrasound?
Prenatal appointments: What to expect during each trimester


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