Today the BabbyDaddy, my mom, and I braved rush hour to drive into the city for an ultrasound and an amnio. The Level II ultrasound was a go and clear of markers for Down syndrome, but I measured at 15.5 weeks along. The consulting doctor suggested my risk of amnio-induced miscarriage would drop if I waited a week or two because the chorionic and amniotic membranes may not be fused yet. For those not in the know - I certainly wasn't - poking the meganeedle into one's womb before the membranes have fused can cause "tenting". Heady stuff, no?
We ended up opting for the MaterniT21 screening, which has an accuracy rate that's roughly 1% lower than the accuracy rate of amniocentesis. Which doesn't, I'm somewhat appalled to say, guarantee I won't go back for an amnio because a prenatal karotype seems to me overall more reassuring (or definite) than a test that measures the ratio of free-floating fetal DNA in my bloodstream.
It's funny, really. If someone had offered me the MaterniT21 test first, before the triple screen, and it had given me a negative result for Down syndrome, I wouldn't have questioned the results. Just like how with P. I never questioned the good numbers on the triple screen, even though P. had bilaterial choroid plexus cysts early on. But with the initial Down syndrome risk on the triple screen, even with an ultrasound showing no markers for DS, I'm leery of taking the results of the MaterniT21 test as gospel. Even though the accuracy rate is way up there and, according to the doctor, the tech has been around since the 90s but it's only now that it's approved for consumer use.
If you were me, what would you do? Trust a negative result on the MaterniT21 test - if indeed my result is negative - or go whole hog and schedule the amnio anyway? I'd definitely welcome your input!