Comparing three screening strategies for combining first- and second-trimester Down syndrome markers

Area of Science:

• Maternal-fetal medicine
• Prenatal diagnostics
• Genetics

Background:

• Down syndrome screening involves combining first- and second-trimester markers.
• Various screening strategies exist, each with unique tradeoffs.

Purpose of the Study:

• To analyze the choices and tradeoffs of three Down syndrome screening strategies.
• Compare sequential, contingent, and integrated screening methods.

Main Methods:

• Utilized published marker distributions for Down syndrome and unaffected pregnancies.
• Integrated maternal age and Down syndrome risk data into a statistical model.
• Compared sequential, contingent, and integrated screening approaches.

Main Results:

• Integrated screening is more efficient than sequential and contingent strategies.
• Sequential and contingent strategies can be adjusted for efficiency based on risk cutoffs.
• Increasing the false-positive rate from 2% to 5% improves detection rates from 85% to 91%.
• Sequential and contingent methods allow for early detection of most Down syndrome cases.

Conclusions:

• Integrated screening is the most efficient method.
• Sequential and contingent strategies can be optimized for efficiency and early detection.
• Further intervention trials are necessary to evaluate real-world performance and acceptability.