Clinical effect of expanded non-invasive prenatal testing for serological screening of fetuses with high-risk for Down's syndrome

Objective: To investigate the clinical effect of expanded non-invasive prenatal testing (NIPT-plus) for serological screening of fetuses with high-risk for Down's syndrome.

Methods: To retrospectively study the screening results, prenatal diagnosis and pregnancy outcomes of 1561 midterm pregnant women underwent NIPT-plus in our center from September 2018 to December 2019 due to serological screening with high-risk for Down's syndrome(≥ 1/270).

Results: 45 pregnant women had a high-risk with a detection rate of 2.88% (45/1561) of 1561 pregnant women who performed NIPT-plus. 40 pregnant women underwent invasive prenatal diagnosis and 20 cases were confirmed with a positive predictive value of 50.0% (20/40). Statistical analysis showed that NIPT-plus has a high detection rate for trisomy 21, sex chromosomal aneuploidy, and MMS in the 0.1/90 group, but with a positive predictive value lower than the other two groups.

Conclusions: The detection rate and PPVs of NIPT-plus in different groups of Down's high-risk pregnant women was different. NIPT-plus can reduce the pressure of prenatal diagnosis and can be used as a screening method for Down's syndrome with high risk in pregnant women.