Down Syndrome Screening
When Is Down Syndrome Screening Done? There are two main timeframes for screening:
1st Trimester Screening (Weeks 10–13) Combined First Trimester Screening includes:
- Nuchal Translucency (NT) ultrasound (measures fluid at the back of baby’s neck)
- Blood test (checks hCG and PAPP-A hormone levels) When: Between week 11 and 13+6 days Most accurate non-invasive early screening Combines with maternal age and other risk factors to estimate likelihood
2nd Trimester Screening (Weeks 15–22) Quad Screen / Triple Test checks:
- AFP (alpha-fetoprotein)
- hCG
- Estriol
- Inhibin-A (quad test only) When: Best done between weeks 16–18, but available up to 22 Can be done if 1st trimester screening wasn’t performed
Optional: Non-Invasive Prenatal Testing (NIPT)
- Highly accurate blood test (99%+ detection rate)
- Checks for Down syndrome and other trisomies (13, 18)
- Analyzes fetal DNA from a sample of the mother's blood When: From week 10 onward Very accurate + safe Not always covered by insurance unless high-risk or advanced maternal age
Why Do Screening?
- Provides a risk estimate, not a diagnosis
- Helps you make informed decisions about further testing
- Allows time to prepare emotionally, medically, or practically
Should You Screen? Screening is optional, not mandatory. Some reasons people choose to screen:
- Age over 35
- Reassurance or preparedness
- Medical planning
- Personal values or decision-making preferences