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Pregnancy Tests -
Baby
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Down Syndrome.
What is Down syndrome?
Down syndrome is a condition caused by a defect in the baby's chromosomes. A baby is mentally retarded and may have a somewhat dwarfed appearance, with a sloping forehead, short, broad hands, a flat nose and low-set ears. He or she may also have heart problems, gastrointestinal defects or leukemia.
How can Down syndrome be diagnosed?
Down syndrome can be diagnosed during pregnancy by amniocentesis; alpha-fetoprotein, triple screen, quad screen and other blood tests; chorionic villus sampling and ultrasound (in some cases). A blood test that measures HCG and pregnancy-associated protein A may be helpful in detecting Down syndrome. If abnormal amounts are in the mother's blood, amnio-centesis or chorionic villus sampling may be recommended for further evaluation.
A new urine test, not yet available commercially, holds promise as a prenatal predictor of Down syndrome. Urine is examined for hyperglycosylated HCG (HHCG). Combined with ultrasound measurements, the results are valuable in detecting the problem.
Another new test, called nuchal translucency screening, combines detailed ultrasound, a blood test and the mother-to-be's age to gauge a woman's risk of having a baby with Down syndrome. This test is not widely available, but there are no known risk factors. Results depend on the accuracy of the ultrasound test.
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