Women's uptake of non-invasive DNA testing following a high-risk screening test for trisomy 21 within a publicly funded healthcare system: findings from a retrospective review.

Objective: The objective of the study was to evaluate the uptake of non-invasive cell-free fetal DNA screening test (NIDT) after a high-risk screening result for trisomy 21 METHODS: Association between maternal and pregnancy characteristics on women's test choice was assessed after adjusting for confounding factors in Hong Kong Chinese women who had a high-risk (term risk ≥1:250) first-trimester or second-trimester screening test at three public hospitals. Main outcome measures were rate of declining further testing and obstetric and maternal factors impacting on patient's selection of testing options.

Results: Compared with the pre-NIDT period, the availability of NIDT resulted in a 45% (P < 0.001) reduction in the rate of refusal for further testing and a decrease from 92.2% to 66.7% in the use of invasive diagnostic test after a positive screening test. Nulliparous women with a spontaneous [adjusted odds ratio (aOR) = 2.18, 95% confidence interval (CI) 1.63-2.92] or assisted reproduction pregnancy (aOR = 3.95, 95% CI 1.6-9.32) were more likely to choose NIDT. Women with an adjusted risk of '>1:10' (aOR = 7.36, 95% CI 4.22-12.8) and '1:10 to 1:50' (aOR = 1.53, 95% CI 1.01-2.32) were more likely to opt for chorionic villi sampling or amniocentesis.

Conclusions: NIDT reduced the refusal rate. Uptake of NIDT was highest in pregnancies of nulliparous women.