1st Trimester Prenatal Screening

We opted to do the 1st trimester prenatal screening test for Down syndrome with this pregnancy. We did it in not just one but two blood draws, making it a sequential screen which results in a more accurate detection rate.

Here are a few excerpts from the genetic counselor's letter after our first meeting several weeks ago:

Ria is 31 years of age and was in the 12th week of her second pregnancy. She and her husband have a son, Matthew, with the trisomy 21 form of Down syndrome. They have a pre-existing risk for Down syndrome of 1 in 210 and for trisomy 18 of 1 in 1,072.

First Trimester Screening assesses the risks for both Down syndrome and trisomy 18 between 11 and 13 weeks gestation based on maternal age, nuchal translucency, hyperglycosylated hCG and PAPP-A. Studies have shown detection rates of about 83% for Down syndrome and 75% for trisomy 18.

We also discussed the option of a sequential screen. This assesses the risks for Down syndrome based on maternal age, nuchal translucency, blood work in the first trimester (hyperglycosylated hCG and PAPP-A), and blood work in the second trimester (AFP, hCG, uE3, DIA). Studies have shown detection rates of approximately 92% for Down syndrome and 90% for trisomy 18. The detection rate is 80% for open neural tube defects and is based on second trimester AFP only.

I had the second blood draw in my 16th week of pregnancy. The results came a few days after the second drawing showing the risk for my baby to have Down syndrome of less than 1 in 5,000 and a risk for trisomy 18 of less than 1 in 5,000. The genetic counselor says these numbers represent the lowest possible risk. The screening test doesn't give a "yes" or "no" result. We knew this of course. We also knew that whatever the results, it wouldn't change our minds about our baby. We just wanted to be "in the know".

What I didn't know was how unaffected I would feel about the numbers. The results of the prenatal screening test didn't mean very much to us, except to know how high or low our risk was to have another child with Down syndrome. Maybe I'd feel some sort of relief or happiness if I didn't have Matthew and had no idea about Down syndrome. That would be just natural, wouldn't it? But honestly, I was neither happy nor upset. They're just numbers. I'd feel the same way if our risk was higher. When we had Matthew, our odds were 1 in 1,100 - better than the odds for winning the lottery. These odds also don't tell us what other possible special needs our baby may have and we know every kiddo needs help with a few things here and there growing up. Every child is different.

Would I recommend the 1st trimester prenatal screening test to other expectant moms? Sure. Mainly because it's non-invasive unlike the diagnositc tests like CVS and Amniocentesis. It's a personal decision. Just keep in mind that this is a screening test that merely gives you odds, not a definite "yes" or "no", no matter how accurate studies deem it to be. I see it as another peek into "what could be", a chance to get to know my baby, and a chance to prepare for our baby's arrival - most especially if our 'risk factor' was higher.

In reality though, how can one truly be 100% prepared? There are so many variables in life. Down syndrome is not the end of the world. One of Matthew's greatest gifts to us is how he has opened our hearts and minds to the many possibilities in this world. This is something any prenatal screening test does not detect - the value of a life and how it will impact yours.