Nuchal translucency and first trimester biochemical markers for down syndrome screening: a cost-effectiveness analysis.

OBJECTIVE The purpose of this study was to perform a cost-effectiveness analysis that compared the first- and second- trimester screening tools for Down syndrome. STUDY DESIGN A decision tree was designed that compared four possible screens for Down syndrome: (1) current second- trimester expanded maternal serum alpha-fetoprotein test (AFP), (2) first-trimester nuchal translucency screen, (3) first-trimester serum screen, and (4) combined first-trimester screen with both nuchal translucency screen and a serum screen. Incremental cost-benefit and cost-effectiveness ratios were calculated that compared the first-trimester screens with expanded alpha-fetoprotein. RESULTS The combined screen (nuchal translucency screen + first-trimester serum screen) identified 3,833 Down syndrome fetuses, the nuchal translucency alone identified 3,413 Down syndrome fetuses, and the first- trimester serum screen identified 2,993 Down syndrome fetuses. Each of these screens was an improvement over the current expanded AFP screen, which diagnosed 2,446 Down syndrome fetuses. It would cost $98,381 for each additional Down syndrome case that would be identified by nuchal translucency alone, with a benefit-to-cost ratio of 4.85. The addition of the first-trimester serum screen is still cost-effective compared with expanded AFP; the cost would be $319,934 for each additional Down syndrome fetus who was identified, which would be a benefit-to-cost ratio of 1.57. CONCLUSION First-trimester screening for Down syndrome with nuchal translucency screening alone or with serum markers is more clinically effective and cost-effective than the current expanded AFP screen that is being used.