Down Syndrome Risk Calculator
Calculate the risk of Down syndrome during pregnancy based on maternal age, test results, and ultrasound markers. Understand risk factors and probability.
Step 1: Maternal Details
Understanding Maternal Age Risk
The risk of Down syndrome increases with maternal age. At age 25, the risk is about 1 in 1,250. By age 35, it’s about 1 in 350, and by age 45, it’s approximately 1 in 30.
Step 2: Test Results
About Screening Tests
First trimester screening combines NT measurement with blood tests (PAPP-A and beta-hCG). NT measurements above 3.5mm are considered high risk. MoM values above 2.0 for beta-hCG or below 0.5 for PAPP-A increase risk.
Down Syndrome Risk Results
Estimated Down Syndrome Risk
Down Syndrome Risk by Maternal Age
| Maternal Age | Risk at Birth | Risk at 12 Weeks | Recommended Testing |
|---|
Risk Factor Analysis
Down Syndrome Risk Formula
Combined Risk = (Age Risk) × (NT Factor) × (Biochemical Factor) × (Other Factors)
The combined risk is calculated using the maternal age-related risk multiplied by likelihood ratios derived from NT measurement, biochemical markers (PAPP-A and beta-hCG), and other ultrasound findings.
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