The Harmony Test – Pros and Cons

If you’re pregnant for the first time, or pregnant with your second or third baby you may not have encountered the Harmony Non-Invasive Screening Test (NIPT). More and more doctors are offering the test and women are unsure about why it is better than the standard first trimester tests.

All pregnant Australian women are offered pregnancy screening within the first 12 weeks of pregnancy to screen for chromosomal abnormalities and structural abnormalities of the foetus. This screening takes the form of a combination of a maternal serum blood test and an ultrasound scan. The scan looks at the nuchal fold on the foetus’ neck, which is a strong indicator of possible chromosomal abnormalities. The results of the scan, combined with the results of the blood test can provide the mother with a possible risk of abnormalities in her baby. It is not definitive and a positive result requires further testing through an amniocentesis or CVS.

The Harmony test is offered to women and as an alternative to the standard screening blood test. It differs from the standard test because the sample of blood taken tests for the foetus’ DNA in the mothers’ blood stream. This is enables testers to determine a likelihood of chromosomal abnormality.

Here are some of the pros and cons to having the newer Harmony test:

Pros

• The Harmony test is more accurate in determining the likelihood of chromosomal abnormalities than standard testing.
• It has a higher detection rate which means if there is a chromosomal abnormality the Harmony test is more likely to pick it up compared to standard 12 week testing.
• Lower false positive rate, which means less women will be sent for invasive testing such as a CVS or amniocentesis.
• Because it is a blood test there is no risk to the foetus.

Cons

• The Harmony test cost around four times more than the standard blood test, with the price ranging between $400 – $450.
• It is unable to detect major structural abnormalities because it does not look at the foetus. Traditional testing combines a blood test with an ultrasound so medical practitioners are able to see how the foetus is developing. Around 60 percent of structural abnormalities are detected through ultrasound so it is recommended to have an ultrasound along with the Harmony test.
• The Harmony test can only look for Down syndrome, Trisomy 13, 18 and sex chromosomes. While these are the most common, they only make up 70 percent of chromosomal abnormalities. An ultrasound detects a thick nuchal fold which can occur in a number of other chromosomal and non-chromosomal abnormalities.
• The results are not definitive so if the Harmony test returned a positive result, more invasive testing would be required for a definitive result. Even if you are given a low risk result there is still a chance your baby may have a chromosomal abnormality.
• There is a small risk of test failure, meaning that in some cases the test returns no result. It is estimated that between one to four percent of tests will fail.

Who Should Have the Harmony Test?

Because of the limitations of the test it is recommended that women are offered counselling around whether or not to have the test. Taking the harmony test after a high risk result from standard first trimester screening may offer a clearer picture of the likelihood of chromosomal abnormality. It is also a good option for women who do not want to risk the more invasive testing of a CVS or amniocentesis.

Why Is It Being Offered So Frequently?

While there is wide spread acknowledgement that the Harmony test does have some limitations, compared to the standard combination of blood test and ultrasound scan, it offers with increased accuracy. A scan is recommended to detect conditions outside the scope of the test so the mother has a more holistic view of her over risk of abnormalities.

Doctors are routinely offering the test to pregnant women as it is considered best practice to offer the latest technology where it is available. This provides the mother with the opportunity to choose which option is best for her and her family.