On December 31, 2007, the last day of last year, I received the second trimester genetic screening test—Quad Screen AFP. The Quad Screen detects up to 70%-79% of Down syndrome cases, 60% of trisomy 18 cases and 80% of open neural tube defects.
Based on the brochure of prenatal screening from Quest Diagnostics, Down syndrome (trisomy 21) is a condition caused by an extra copy of chromosome number 21. Babies with Down syndrome have a distinct physical appearance and some degree of mental retardation. Overall, out of every 800 pregnancies, approximately 1 will carry a baby with Down syndrome (trisomy 21). The number of Down syndrome cases increases with maternal age.
Trisomy 18 (Edwards syndrome) is a condition caused by an extra copy of chromosome number 18. Babies with trisomy 18 have severe mental retardations and multiple birth defects. Overall, out of every 5000 pregnancies, approximately 1 will carry a baby with Edwards syndrome. The number of Edwards syndrome cases increases with maternal age.
The neural tube develops into the spine and brain of the baby very early in pregnancy. If the neural tube doesn’t develop properly, the result can be a defect in the baby’s spine and/or brain. Neural tube defects occur in 1-2 out of 1000 births and are not associated with the mother’s age.
A few weeks later, I called the doctor’s office and was told all the results were negative. Although a positive screening test result will not change my mind to have this baby, both negative results of the first trimester and second trimester screening tests still make me feel much more comfortable about my baby’s health conditions.
Best wishes to all the mothers-to-be and best luck to their babies! Let the world have one more healthy and happy baby!
Related posts:
More understanding on PAPP-A and Down syndrome
One baby might be at the increased risk of Down syndrome…
My first trimester screeing was negative!
The first trimester test
AFP results are negative!
From Lina, Healthy Pregnancy, Pregnancy | Lina | 
January 18, 2008 2:31 pm | 
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