Age-based differences in the predictive accuracy of a one-size-fits-all risk-cutoff value in prenatal integrated screening for Down syndrome

Objective: The objective of this study is to assess variation in detection and false positive rates and adverse pregnancy outcomes across different age groups when a one-size-fits-all risk-cutoff value, such as 1/270, is used in integrated screening for Down syndrome. Method: A Monte Carlo simulation was utilized to estimate the detection and false positive rates as well as adverse pregnancy outcomes. Results: Using a one-size-fits-all risk-cutoff value, such as 1/270, can result in considerably high variations in detection and false positive rates across maternal ages and lead to a higher than the minimum possible total number of adverse outcomes. Conclusion: Our findings indicate that the one-size-fits-all risk-cutoff value of 1/270, commonly used in DS screening, should be revisited and alternative (possibly age-based) cutoff values and strategies should be considered.