Every parent-to-be experiences anxiety during pregnancy – after all, we all want our children to be as healthy and happy as possible. Although there are a number of tests available informing you of whether you should be concerned about genetic abnormalities before your baby’s birth, Non-invasive Prenatal Testing (NIPT) has emerged as a popular, and highly-accurate, option.
If you’ve been pregnant before, you’ll probably have had the usual blood test and ultrasound exam that are used to calculate your baby’s risk of conditions such as Down’s Syndrome. You may even have been advised to have an amniocentesis or chorionic villus sampling (CVS).
There’s a place for each of these screens, but there’s also a reason why awareness of NIPT is on the up: it carries less risk than invasive procedures, and is more accurate than screens based on scoring systems, but the NIPT is entirely elective.
How does the Non-Invasive Prenatal Testing work?
The test itself is simple: blood is drawn at around the tenth week of pregnancy, and the results are available seven to 10 days later.
By detecting the placental NA that circulates within your blood, or cell-free DNA, the test is able to find out if there are common chromosomal abnormalities such as Down’s Syndrome in the foetus, explains Professor Ermos Nicolaou, Academic Head of the Division of Maternal and Fetal Medicine at Wits.
Professor Nicolaou notes that testing is elective. However, in some cases, it would be highly advised. According to Kelly Loggenberg, Genetic Counsellor at Next Biosciences, NIPT testing is usually recommended for older moms, or in cases where an intermediate or high risk has been detected on first or second trimester screenings. Your doctor may also suggest a test if there have been chromosomal abnormalities in previous pregnancies – or if you would simply like more information about your pregnancy. You could, of course, rely on a normal ultrasound for such information – but NIPT provides additional peace of mind, because an ultrasound cannot rule out the possibility of a chromosomal abnormality. “Ultrasounds focus on structural abnormalities, while NIPT concentrates on chromosomal abnormalities,” Kelly observes. “Both tests are complementary, and both are important as part of routine pregnancy management.”
Why this test rather than others? Because, says Kelly, “the guidelines provided by the South African Society of Obstetricians and Gynaecologists are that if money wasn’t an issue and there were more than enough experts in the country, the very best screening would be a combination of NIPT with an expert NT scan, an expert fetal anatomy scan and a repeat expert scan in the last trimester. This combination could, theoretically, detect 99% of all Down’s Syndrome cases, a list of other genetic conditions and the majority of physical fetal abnormalities.” However, medical aid schemes will only cover the cost (or part thereof) of the test if certain criteria is met to deem the test medically necessary.
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How much does the NIPT cost?
Professor Nicolaou notes that there are different kinds of NIPT tests: some are geared to detecting Down’s Syndrome only; others test for other chromosomal abnormalities such as Trisomy 18 and Trisomy 13, sex chromosomal abnormalities, or even smaller genetic defects.
Costs for these tests range from R4 000 to around R12 500, although this may be covered by your medical aid if the screening for Down’s Syndrome has shown a high risk. If this is not the case, and you’ve chosen to have the test to assuage your anxieties, your medical aid may choose not to provide cover.
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The final analysis
Professor Nicolaou says that although NIPT tests are usually “very accurate”, 100% accuracy is not guaranteed. You may wish to consider an amniocentesis or CVS if you receive a positive test result. Even so, the information provided by the test is highly valuable – as is the peace of mind that may come with the results.