
Calculating Risk of Down's Syndrome from Maternal Serum alpha-Fetoprotein and HCG
Specialty: | Obstetrics & Gynecology Pedatrics Genetics |
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Description: | The risk of a fetus being affected by Down's syndrome can be calculated based on the maternal a priori risk consequent to age, AFP multiple of the mean, and HCG multiple of the mean. The distributions for AFP and HCG are assumed to fit a bivariate log-gaussian distribution in both normal and Down's pregnancies. AFP is typically 30% lower in Down's pregnancies, while HCG is 200% higher. |
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