An interview with geneticist Diana Bianchi provides hope:
In addition, something that doesn’t get a lot of attention in the DS community is the possibility that if you could noninvasively diagnose DS at ten weeks you could consider the possibility of fetal treatment if you decided to continue the pregnancy.
What sort of therapy are you envisioning?
We’ve been studying the amniotic fluid transcriptome. It turns out that the cell-free RNA floating in the amniotic fluid is coming from multiple organs, including the fetal brain. And so, in a PNAS paper in 2009, we took a systems biology approach to the second trimester living fetus with Down syndrome, [and asked] what’s wrong compared to the euploid fetus? And there were some profound functional differences, most notably oxidative stress. We hypothesized that if you specifically addressed the transcriptome, and took a personalized medicine approach, you might improve neurocognitive outcome—that’s the endpoint for most DS researchers. There’s a Roche trial going on right now treating adults with DS. My vision would be to convincingly demonstrate that you could treat the pregnant woman with meaningful personalized treatment designed for the fetus, because there’s so much neural development going on in utero. If you wait to treat until birth, it’s not just that you’re losing six months—you’re losing huge biological windows of opportunity to influence neurogenesis.
Of course this is at the research stage. Still, it might be something to look out for. In the future we may need to promote these therapies to save lives.
And about the rate of abortions for DS babies, she says:
The often quoted 90 percent termination rate is not an accurate number—it is more like 65 percent.
I put it forward in the interests of fact-gathering. It's still a high rate.