Uptake of non-invasive prenatal testing by Japanese women.

Abstract

Since April 2013, Hokkaido University Hospital (HUH) has participated in a multicenter clinical trial in which non-invasive prenatal testing (NIPT) for fetal trisomies 21, 18 and 13, using fetal cell-free DNA from maternal plasma, has been provided for women at increased risk of trisomy. It was expected that the number of pregnant women seeking NIPT would be high, because of both the presence of numerous reports in the Japanese media prior to commencement of the clinical trial and the knowledge that NIPT, in addition to being non-invasive, is a procedure with high sensitivity and low false-negative rates among women at higher risk of fetal aneuploidy1. We did not expect that there would be a corresponding increase in the number of women undergoing invasive confirmatory tests, such as chorionic villus sampling (CVS) and amniocentesis. However, as of yet no data have been published regarding changes in the number of women seeking prenatal screening, including the combined test2, first-trimester ultrasound examination3, quad screen4 and NIPT, or in the number undergoing invasive confirmatory tests following the introduction of NIPT in Japan. During the 2 years preceding the clinical introduction of NIPT at HUH, 75 and 144 women underwent at least one prenatal screening test in the Japanese fiscal years beginning in 2011 and 2012, respectively. This increased markedly to 369 women after the introduction of NIPT in 2013 (Table 1). This change was due entirely to the number of women undergoing NIPT, accounting for 70.7% (261/369) of all women who had at least one prenatal screening test in 2013. However, there was no corresponding increase in the number of women undergoing invasive confirmatory tests, such as CVS or amniocentesis. In 2011, 18 of 75 (24.0%) women who underwent prenatal screening subsequently underwent further invasive confirmatory tests, as did 28 of 144 (19.4%) women in 2012. This decreased to 18 (4.9%) of 369 women in 2013 after the introduction of NIPT (Table 1). In the 3-year study period, 61 (18.7%) of 327 women who underwent prenatal screening other than NIPT alone underwent invasive confirmatory tests, while only three (1.1%) of 261 women who underwent NIPT underwent such tests (Figure 1) (P < 0.0001, Fisher's exact test). Among 237 women with negative results for prenatal screening other than NIPT, 12 (5.1%) underwent CVS or amniocentesis for confirmation, while no one with negative NIPT results underwent these tests. This suggests that women who underwent NIPT accepted the results of the technique as reliable. In Japan, the number of pregnant women undergoing prenatal screening has been traditionally lower than that in some European countries and the USA5. However, with the introduction of NIPT, the number of women seeking prenatal screening has increased markedly, suggesting a potential need for prenatal diagnosis that had been hidden because sufficient information regarding prenatal screening was absent and because there was concern among pregnant Japanese women about the risk of adverse events associated with CVS and amniocentesis. NIPT may become accepted in Japan, which could lead to a reduction in the number of invasive procedures for detection of fetal trisomies in the near future. R. Akaishi, T. Yamada*, S. Kawaguchi, T. Kojima, T. Koyama, T. Umazume, M. Morikawa, K. Cho and H. Minakami Department of Obstetrics, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo, Japan *Correspondence. (e-mail: [email protected])