If your fetus has been diagnosed as having Down syndrome or is simply at high risk, please spend some time to learn more about the condition.
Over the last fifteen years, these were done in the 15th to 18th week of pregnancy.
Recently, another marker called PAPP-A was found to be of use even earlier.
In the 1980s and 90s, the results of the prenatal tests were expressed to parents as "high risk" and "low risk," depending on whether the risk result was above or below an arbitrary cutoff point at 1 in 250.
(I have seen the cutoff as low as 1 in 200 and as high as 1 in 270.) The reason for choosing that cutoff value was based on the risk of complications from an amniocentesis procedure.
A very important consideration in the screening test is the age of the fetus (gestational age).
The correct analysis of the different components depends on knowing the gestational age precisely. Once the blood test results are determined, a risk factor is calculated based on the "normal" blood tests for the testing laboratory.Note: The subject of prenatal testing for Down syndrome is an emotionally charged one.I am presenting this essay as a guide to parents who are faced with the prenatal tests offered by their doctor.Likewise, h CG in a Down syndrome pregnancy would be greater than 1.0 Mo M.In the serum screening, the lab reports all results in either this way or as a total risk factor calculated by a software program.The average of normals is called the "population median." Test results are sometimes reported to doctors as "Multiples of the Median (Mo M)." The "average" value is therefore called 1.0 Mo M.