g: Prenatal Testing for Down Syndrome (Trisomy 21)
NIPT (cfDNA screening): This is a screening test. Among positive results, there is typically a 5–30% chance the baby is born without Down syndrome, with the rate varying significantly by maternal age. Younger mothers tend to have higher false-positive rates due to lower background prevalence of Trisomy 21.
Diagnostic tests (amniocentesis or CVS): These provide definitive results with accuracy >99.9%. Once confirmed positive, the chance of the baby being born without Down syndrome is less than 0.1%.
Jesse & Ashley Ridgway Case
YouTuber Jesse Ridgway (age 33) and his wife Ashley (age 31) publicly shared that they terminated a pregnancy after a diagnosis of Trisomy 21. Key facts from their statements:
Married: October 2025
Pregnancy announced: March 2026
NIPT screening (Natera): April 2026 → 95% chance of Trisomy 21 (baby was a boy). They noted concerns about possible false positives.
Amniocentesis: Results received around May 27, 2026 → Confirmed Trisomy 21
Termination: Early June 2026 (after diagnostic confirmation)
Testing Pathway & Probability Clarifications
The couple followed the standard pathway: NIPT screening first, followed by confirmatory amniocentesis.
The 95% was the Positive Predictive Value (PPV) from the NIPT. At age 31, this was a relatively strong result, meaning there was roughly a 5% chance the baby would be born without Down syndrome if they had relied on the screening test alone.
The >99.9% refers to the accuracy of amniocentesis. After confirmation, the chance of a normal (non-T21) outcome dropped to <0.1%.
Maternal age was already factored into the 95% NIPT result. However, once amniocentesis confirmed the diagnosis, age no longer meaningfully affected the probability.
In this case, the couple waited for diagnostic confirmation before making their decision. The initial 95% NIPT result (which already accounted for Ashley’s age) left some uncertainty, which the amniocentesis largely removed.