Fig 1.
Flow chart of participants recruitment and overall design.
FTS, first-trimester screening test; Quad, quadruple test; NIPT, non-invasive prenatal testing; PND, prenatal diagnosis test; TOP, Termination of pregnancy.
Table 1.
Performance of prenatal screening test.
Table 2.
Prevalence of trisomy.
Table 3.
Detection rate and false positive rate of serum screening tests from other countries.
Table 4.
Prevalence of trisomy in countries worldwide.