Prenatal testing — confidence based on knowledge
Modern prenatal tests assess chromosomal risk non-invasively from a maternal blood sample.
cffDNA / NIPT
The most accurate non-invasive screening for trisomies. Available from week 10. Sensitivity >99% for trisomy 21, >97% for trisomies 18 and 13. False-positive rate <0.1%.
Combined first-trimester test
PAPP-A + beta-hCG combined with 1st trimester ultrasound (NT). Performed at 11–13+6 weeks.