Screening for major aneuploidies at 10 weeks of gestation in an unselected population: comparing the combined test to the non-invasive prenatal testing with rolling-circle replication (SAPERER study).

OBJECTIVE

Non-invasive prenatal testing (NIPT) is the most accurate method for screening major trisomies. However, its diffusion is limited by high costs, and in many countries, the first-tier combined test remains the standard of care. This study compared the performance and outcomes of the Vanadis NIPT platform at 10 weeks' gestation with the combined first-trimester test.

METHODS

This prospective cohort study included unselected women undergoing both first-tier NIPT and combined tests. Positive results led to genetic counselling and invasive procedures. Diagnostic accuracy was compared.

RESULTS

Vanadis NIPT detected more trisomy 21 and 18 cases (T21 sensibility 93.3%, 95% CI 83.3-98.2; T18 sensibility 82.4%, 95% CI 56.6-96.2) than the combined test (T21 sensibility 84.9%, 95% CI 72.4-93.3; T18 sensibility 76.5%, 95% CI 50.1-93.2), although the differences were not statistically significant, and fewer cases of trisomy 13; 30% (95%CI, 6.7-65.3) versus 87.5% (95%CI, 47.4-99.7), p=0.0147. Overall, the false positive rate was significantly lower for NIPT compared to the combined test (0.2% versus 4.1%, p<0.001). More than 99% of women received a risk assessment following the NIPT assay, with most reports provided during the first trimester of pregnancy. Among 18,383 women, positive results were nine times less frequent with NIPT than with the combined test, with an estimated 88% decrease in genetic counselling associated with a drop of 74% of invasive procedures after post-test counselling.

CONCLUSION

NIPT is a reliable first-trimester screening method that provides early risk assessments for major trisomies, drastically reducing unnecessary medical procedures. If confirmed, the lower sensitivity of the Vanadis NIPT at ten weeks requires attention and should be evaluated and discussed with women. https://www.

CLINICALTRIALS: gov/search?cond=NCT04437992.