Contingent screening for Down syndrome is an efficient alternative to non-disclosure sequential screening

Area of Science:

• Maternal-fetal medicine
• Prenatal diagnostics
• Genetics

Background:

• Down syndrome screening is crucial for prenatal care.
• Current methods like the Integrated test require markers from both trimesters.
• A need exists for strategies offering earlier screening completion.

Purpose of the Study:

• To present a contingent Down syndrome screening strategy.
• To enable early screening completion for a majority of women.
• To compare this strategy with the non-disclosure sequential screening (Integrated test).

Main Methods:

• Utilized two first-trimester risk cut-offs to categorize results: positive, negative, or intermediate.
• Employed multivariate Gaussian modeling and Monte Carlo simulation for analysis.
• Estimated false-positive rates based on fixed detection rates and evaluated early test completion rates using SURUSS trial parameters.

Main Results:

• Screening completion in the first trimester for 75% of women yielded an 85% net detection rate (30% early, 55% second trimester).
• The false-positive rate was only 0.1% higher than the Integrated test.
• First-trimester screen-positive rate was 0.1%; second-trimester rate was 4.7% for continuing participants.

Conclusions:

• Contingent screening offers comparable results to the Integrated test with earlier completion for most women.
• This strategy demonstrates high detection rates and a low false-positive rate.
• Further large-scale prospective studies are recommended to assess psychological impact and practicability.