Friday, May 29, 2009

Down Syndrome Awareness -- Questions About Incidence

It just occurred to me that I have not seen any new statistics on the incidence of Down syndrome in a long time. I'd be interested to know if it has changed at all worldwide and, especially, locally -- in the US, NY and Long Island.

The reason I'm curious about this is that many professionals have said to me that Down syndrome is no longer just or predominantly afflicting the children of woman over 40 anymore but that it is spreading down towards woman who are [often much] younger than 40 more and more. Are there statistics that support this statement? If so, has the 1 in 800 before 40 and 1 in 100 after 40 statistics changed at all? Has anyone re-examined and/or recalculated recently given this "trend"?

Also, I have heard it quoted many times that 92% of all fetuses diagnosed with Down syndrome in utero are aborted. I also know that with all the in vitro births, an embryo with Trisomy 21 would NOT be implanted. As such, I would tend to think the incidence statistics would also be changing... Unless:

[1] the incidence of Down syndrome is on the rise and terminations of fetuses with DS counteracts that trend or [2] these terminations are localized (to the NY area?) and don't impact the statistics much or [3] the two trends together erase each other?

I've heard nothing new... Have you?


  1. I, too, would like to know the latest numbers because I am hoping the percentage of abortions has come down. Btw, I read the Happiness Project too!

  2. I just read this open letter and remembered your question in this post.

    He makes a good point about the 90% statistic and says the actual number is more like 45% (in Britain anyway). It was very interesting and has me wondering even more about the real statistics on Ds and live births.