First-trimester Down syndrome screening in women younger than 35 years old and cost-effectiveness analysis in Taiwan population

Summary Objectives Outcome of the first‐trimester Down syndrome screening in younger population was less reported before. We present the outcome of this screening in Taiwanese women younger than 35 years old. We also test whether or not the first‐trimester Down syndrome screening of women 35 years old routinely receiving amniocentesis is cost‐effective compared with all pregnant women screened with this test in the setting of increased maternal age. Methods From 1999 to 2007, the first‐trimester Down syndrome screening including nuchal thickness, pregnancy‐associated plasma protein A and free β‐hCG are provided to 10 811 singleton women