There's a relatively new test out there called the nuchal translucency screening, which is a screening (read: not a 100% sure thing) for Down's Syndrome (Trisomy-21) and Trisomy-18 (a terribly scary disease that almost always results in death soon after birth). This screening is the combination of a (maternal) blood test and an ultrasound. The tech takes a measurement of the fluid at the back of the baby's neck. A normal range of length would be up to 10-20mm, and an abnormal range would be 35mm or more. The ultrasound is then compared to the bloodwork, where the levels of two pregnancy hormones are checked to see if those levels are abnormal. In certain chromosomal disorders, the nuchal folds are thicker and the hormone levels are off.
I've already discussed my concerns about not getting prenatal screenings here, so I won't belabor it again. Since my doctor is in the process of having a birthing center built that I could actually use, I thought it would be the responsible thing (again) to find out if there was anything wrong with the baby before we made the decision on where to deliver. When I read that the nuchal translucency (NT) gave a 70-90% accuracy in detecting Down's without requiring things that scare me muchly, like amnio or CVS, I was all for it.
I had to go to the swanky La Jolla hospital to have it done, since it's only done by extremely specialized ultrasound techs. C joined me. The baby was not cooperative, although the shelf of fat from the C-section didn't help either. The tech pushed and prodded and had me get up and shimmy and finally the kid was visible.
Anyway, she ran off to get the results. The doctor came back in and I almost fell over, like, oh my, they sent the doctor to tell us the bad news. But no, everything looks great and he just wanted to look himself.
The results are given as odds. Right now, I'm 1 in 6,600 for Trisomy-21 and 1 in 58,000 for Trisomy-18. That's given as 70% accurate. It'll be combined with another set of bloodwork (the quad screen) in the second trimester for a 90% accurate ratio.
The only other thing is that the ultrasound dated the kid one week earlier than my date, but I'm still not sure I trust the whole gestational dating thing for ultrasounds. The gestational dating for A always put him a week or so behind and smaller than everyone thought. At my last ultrasound at the birth center, the tech said, "Oh, just over six pounds. Small like Mommy." (Mommy was over nine pounds at birth, but that's besides the point.) At the ultrasound in the hospital, the doctor said, "Six, six and a half pounds."
And he was seven pounds, 11 ounces. So I think the ultrasound sizing is a lot of hooey.
But I'll take the NT results.
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