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THE OPTIMAL RISK CUTOFF VALUES FOR DOWN SYNDROME SCREENING CONSIDERING WOMEN ’ S PREFERENCES

Prenatal screening for Down syndrome (DS) based on biomarker levels provides expectant parents with an estimated risk of a DS baby. The risk cutoff value of a prenatal screening test determines the detection and false positive rates and the selection of follow-up procedures, such as an invasive diagnostic test. Women who consider prenatal screening might face two undesirable outcomes: undetected DS live births (DSL) and procedure-related fetal losses (EFL). One-size-fits-all risk cutoff values, such as 1/270, are commonly used in DS screening to recommend diagnostic tests. However, evidence suggests that different women have different preferences about the pregnancy outcomes. The objective of this study is to find the optimal risk cutoff values for DS screening. As no closed-form solutions exist, we use Monte Carlo simulation to solve the proposed model. We find that age-specific risk cutoff values outperform one-size-fits-all risk cutoff values.