Cell-free DNA and contingent screening: Our first year

Area of Science:

• Prenatal Diagnostics
• Genetics
• Maternal-Fetal Medicine

Background:

• Cell-free DNA (cfDNA) analysis from maternal blood shows promise for screening fetal aneuploidies.
• cfDNA can serve as a primary screening tool or be integrated into a contingent model following combined testing.

Purpose of the Study:

• To evaluate the implementation and performance of a contingent cfDNA screening model in a public hospital setting.
• To assess the impact of the contingent model on invasive testing rates and cost-effectiveness.

Main Methods:

• A prospective study enrolled 1272 women undergoing first-trimester combined screening.
• Participants were risk-stratified (high, intermediate, low) with specific pathways for cfDNA testing or invasive procedures.
• Pregnancy outcomes and screening performance were analyzed, including a cost-effectiveness evaluation.

Main Results:

• The study involved 1272 participants, predominantly Caucasian (82.6%) with a median maternal age of 30.
• Invasive testing rates decreased from 3.5% to 2.4% with the contingent model.
• 75.5% of intermediate-risk patients opted for cfDNA testing, while 83.3% of high-risk patients chose invasive testing.

Conclusions:

• The contingent cfDNA screening model effectively reduced invasive procedures in a low-risk population.
• Cut-offs for risk stratification balance detection rates, pregnancy loss, and costs.
• Further research is needed to optimize cut-offs for cost-benefit in specific national contexts.