Is neurodiversity's 92% figure accurate?

One of the main tenets of the neurodiversity movement is that the desire to cure autism and research in that direction will result in prenatal testing and wide scale abortion of autistic fetuses.  They allege the goal of Autism Speaks, The Simon's Foundation and others is to use this to deliberately eliminate autistic people from the human race.  Amanda Baggs and her friends on autistics.org have a tasteless cartoon showing an aborted fetus in a trashcan with the initials CAN embolded on it, indicating that Cure Autism Now, Autism's Speaks predecessor, had this goal in mind.  For this reason, ASAN's leader and Obama appointee Ari Ne'eman has called for a moratorium on all genetic research in autism. 

They cite a figure claiming that 92% of all fetuses with Down's syndrome are subsequently aborted.  Where does this figure come from and how truly accurate is it?  The main source for this statistic seems to be a study  from King's college in London done by Mansfield et. al using figures from the 1980s.  A few other studies have shown similar conclusions with percentages ranging from 80-92%.


According to one source I found,  there have been regional variations in some of the other studies done trying to answer this question.  The various studies have limitations in that they are done in just small areas in various parts of the world and may not be generalizable to all woman pregnant with Down's fetuses in the U.S.A. 

However, the 80-92% rate was not all Down's fetuses but just those who actually underwent prenatal screening.  The 80-92% rate is clearly a selective sample of woman who underwent testing because they would contemplated aborting the trisomy 21 child in the first place.

Bristol Palin, whose youngest brother has Down's, at one time also cited the same figure that activists in the neurodiversity movement use.  She recently corrected the record thanks to Amy Julia Becker, the mother of a Down's daughter who states:


I  just read Bristol’s post about babies who are born with DS being one of the 8%. I love the poem she includes, and I think her point is an important one. Still, I’ve learned recently that it’s an inaccurate number. It’s widely cited by many people, but it’s based on a single study from a single hospital in the 1980′s. Overall, it seems that about 70% of babies prenatally diagnosed with DS are aborted, and that the abortion rates vary greatly from region to region across the US. Moreover, lots of women don’t seek prenatal diagnosis, whether out of ignorance or because they don’t want to risk an amnio or because they don’t think the information is necessary. So out of all babies conceived with DS, 50% are actually born.

So, this figure that ND activists routinely trot out to bolster their crusade against a cure for autism is questionable.  I don't know the exact rate of all Down's syndromes babies that are actually aborted.  However, it's clear that it's not the 90 percent or more who just get the prenatal testing.  This is clearly a misrepresentation on Ne'eman's part and those who think as he does.

This is aside from the fact that autism is not Down's syndrome and they are two different conditions that prospective parents would likely take different attitudes toward.  I doubt there is any way that the ND movement can extrapolate  the true rate of abortion of autistics would be from whatever the number is for Down's is given the hypothetical that such a prenatal test for autism existed.

I realize that neurodiversity proponents will state that even a 50% abortion rate is high.  This is not to say that I believe that even coin-flip rate of abortion for Down's syndrome is acceptable, only that ND's should use accurate information if they want to engage in propaganda and fear mongering tactics.  

Bristol Palin corrected the record.  Perhaps it's time that Ari Ne'eman, ASAN and other ND proponents do so also.