Oral or Poster Presentation
Concurrent Session 4C - Reproductive Science
Introduction: The advent of cell-free DNA (cfDNA) screening has allowed for screening options beyond Trisomies 21 and 18. In Ontario, cfDNA screening for common aneuploidies (Trisomy 21, 18, 13 and sex chromosome aneuploidies) is publicly funded under specific eligibility criteria. Pregnant individuals who do not meet the eligibility criteria can self-pay for this screen. Additionally, individuals can opt to pay to screen for microdeletions. This study aimed to assess the uptake and performance of cfDNA screening for the common autosomal aneuploidies, sex chromosome aneuploidies, and the microdeletions on a population level, and in various clinical contexts including mosaicism.
Methods: This was a population-based retrospective cohort study using BORN Ontario registry data. All singleton pregnancies in Ontario with an estimated date of delivery (EDD) between September 1, 2016 and August 31, 2018 were included.
Results: 24,890 pregnant individuals had cfDNA screening during our study period; 66% of the screens were publicly funded and 34% were self-paid. The sensitivity of cfDNA screening was 100.00% (95% CI: 98.97,100.00) for Trisomy 21, 97.40%(90.93,99.68) for Trisomy 18, 87.50%(67.64,97.34) for Trisomy 13 and 95.00% (75.13,99.87) for Monosomy X. Sensitivity measures for the other sex chromosome aneuploidies yielded wide confidence intervals : 100.00% (47.82,100.00) for 47,XXX, 66.67% (9.43,99.16) for 47,XXY and 100.00% (15.81,100.00) for 47,XYY. We also report an increasing uptake of microdeletion screening during the study period. In our cohort, there were a small number of pregnancies with mosaic aneuploidies that had cfDNA screening, all were detected by the screen.
Conclusion: This represents the first look at the screening performance for non-traditional screening options (other than Trisomy 21 or Trisomy 18) in Ontario. Future studies will focus on the cost analysis and impact on the system that screening for these additional targets may have on our system.