Knowledge of non-invasive prenatal testing among pregnant women

To the Editor: Non-invasive prenatal testing (NIPT) for trisomy 21 and other chromosomal abnormalities using cell-free fetal DNA became available in Australia on a user-pays basis in 2012.1,2 Since then, the price of this highly accurate screening test has fallen as multiple international providers entered the market, including, earlier this year, the first Australian provider.1,3 The growth in the industry and anecdotal evidence both suggest that demand for the test is increasing rapidly.

We undertook a brief survey in a convenience sample of women attending a specialist obstetric ultrasound service located in Perth, Western Australia, for first trimester screening (FTS) between February and April 2015. Ethics approval was provided by the Curtin University Human Research Ethics Committee. The median age of the women was 32.7 years, and 29.1% were of advanced maternal age (over 35 years); 84.3% of the women were of European ancestry; 95.9% of the pregnancies were singletons. Sixty-two per cent of the respondents (139/224) had been aware of NIPT before attending for FTS. Women aware of NIPT were asked whether they had already given blood for NIPT; 38/139 (27.3%) responded that they had. We believe, however, that some women may have believed that the blood collected for FTS was to be used for NIPT, showing a lack of understanding of the FTS process and the distinction between blood collection for FTS and NIPT. Of the women who stated they had not already used NIPT (and excluding another three who did not answer the question), 7.1% (13/183) indicated that they would definitely have NIPT, with a further 74.8% (137/183) indicating that a decision to have NIPT would be based on their FTS results. Of the women who had used NIPT or indicated they would consider using it, 74.4% (154/207) reported they would be willing to pay at least $400 for the test.

The results of this brief convenience survey highlight the high level of NIPT awareness among pregnant women and illustrate the potential demand for this test, but also raise issues about the patients' understanding of screening processes and of the role of NIPT in the screening pathway.

There is currently neither a national approach to NIPT, nor are there recommendations about how NIPT should be integrated into the prenatal screening pathway in Australia, although work is underway.4 Screening strategies that have been proposed include providing NIPT in combination with an ultrasound examination to all women, as an alternative to FTS; offering NIPT to women with pregnancies identified by FTS as high-risk (estimated risk of trisomy 21 of greater than 1 in 300); or, as a variation of this second strategy, offering NIPT contingent on an FTS result, but using more sensitive risk cut-offs.5

Steps should be taken to ensure that women are adequately informed about their prenatal screening choices, the potential pathway resulting from screening, and the benefits and limitations of these tests.