@article {HuangE436, author = {Tianhua Huang and Shelley Dougan and Mark Walker and Christine M. Armour and Nan Okun}, title = {Trends in the use of prenatal testing services for fetal aneuploidy in Ontario: a descriptive study}, volume = {6}, number = {4}, pages = {E436--E444}, year = {2018}, doi = {10.9778/cmajo.20180046}, publisher = {Canadian Medical Association Open Access Journal}, abstract = {Background: In 2014, Ontario augmented its publicly funded multiple-marker screening program for prenatal aneuploidy by incorporating cell-free fetal DNA (cffDNA) analysis for high-risk pregnancies. We assessed trends in the use of multiple-marker screening, cffDNA screening and prenatal diagnostic testing before and after implementation of public funding.Methods: We conducted a descriptive study based on data from the Better Outcomes Registry \& Network (BORN) Ontario. The study population included all pregnant women in Ontario with a singleton pregnancy and an expected date of delivery between July 1, 2012, and Mar. 31, 2016, with pregnancy data captured in BORN. Pregnancy losses and terminations before 20 weeks{\textquoteright} gestation not captured in BORN were excluded. We generated descriptive statistics to show trends and regional variations in use.Results: The study sample included 534 210 singleton pregnancies. After cffDNA screening was funded for specific indications, uptake of multiple-marker screening increased slightly, from 66.5\% to 68.1\% (p \< 0.001). Uptake of cffDNA screening among women with a positive multiple-marker screening result increased substantially, from 3.2\% to 48.8\% (p \< 0.001). In contrast, the rate of prenatal diagnostic testing in this group decreased from 54.8\% to 30.8\% (p \< 0.001). Although women aged 40 years or older are eligible for primary cffDNA screening, only a small decrease in the use of multiple-marker screening was observed in this group. The greatest use of cffDNA screening and greatest decline in prenatal diagnostic testing were seen in women with a level of risk for trisomy 21 of 1:101{\textendash}1:200 based on multiple-marker screening.Interpretation: After public funding of cffDNA screening was implemented in Ontario, there was a significant increase in cffDNA screening and a significant decrease in prenatal diagnostic testing among women with a positive multiple-marker screening result. These changing patterns show the significant impact of public policy and funding decisions on women{\textquoteright}s choices regarding prenatal testing.}, URL = {https://www.cmajopen.ca/content/6/4/E436}, eprint = {https://www.cmajopen.ca/content/6/4/E436.full.pdf}, journal = {Canadian Medical Association Open Access Journal} }