OBJECTIVE: This study aims to analyze differences in characteristics between women who opted for invasive testing after first-trimester combined testing and those who did not.
METHOD: Follow-up was performed in 20 215 combined tests conducted between 2007 and 2011 in the central region of the Netherlands. Multivariate logistic regression analysis compared variables (Down syndrome risk estimate, maternal age, previous Down syndrome pregnancy, IVF/ICSI, parity and nuchal translucency measurement) between different groups.
RESULTS: 65.4% of women with a Down syndrome risk estimate ≥1 in 200 opted for invasive 49 testing. In a multivariate model, women opting for invasive testing were significantly younger (odds ratio 0.92; 95% confidence interval 0.88-0.95) and less likely to have had IVF/ICSI (odds ratio 0.57; 95% confidence interval 0.37-0.87) than women opting out on invasive testing. In this high risk group, women <36 years opted for invasive testing more frequently, regardless of their Down syndrome risk estimate magnitude. Women ≥36 years let the magnitude of the risk estimate count significantly in their decision to opt for invasive testing.
CONCLUSION: Because of the dissimilarity in the offer of prenatal screening and invasive diagnosis in the Dutch prenatal screening policy, women <36 years and women >36 years make different choices when confronted with similar Down syndrome risk estimates.