getting technical

The genetic counselor called me back and she states that the risk ratios I was given *do* take into account the nuchal measurement. Age is also factored in, along with race and weight. So I nosed around the internet to get more info. Here is what I found. It turns out that the nuchal measurement grows as the baby grows. So an average measurement for an 11 week fetus will be smaller than for a 13 week fetus. My baby measured 12w4d (64mm) at the ultrasound, even though I was 12w2d based on my ovulation estimate. For now, I will take it that the baby was 12 and a half weeks for purposes of comparing to the internet numbers. There is a table that shows the measurements for 3000 women at 12 weeks and 2500 women at 13 weeks. The nuchal measurement average for a 12 week fetus would be 1.7mm (mine was 1.4). The nuchal measurement for a 13 week fetus on the average would be 2.0mm. Since my baby measured 12.5 weeks, the nuchal average measurement expected would have been 1.85mm. So my baby's nuchal thickness was much smaller than average. Somewhere below the 25th percentile. FYI, they get scared when the measurements are above the 95th percentile, which would be 2.6mm and 3.0mm at 12 and 13 weeks.

Here is the address of the table I referred to if you are interested:
http://www.greenjournal.org/cgi/content-nw/full/100/4/648/T2

See below for the blood results.