DOWN SYNDROME not necessairly linked to maternal age????

[drosophila]

A friend of mine has given birth to a baby with Down Syndrome and was told by the PAED that there are more cases of DS now with young mothers. SOunded strange to me so I did a google and apparently another big factor is the age of the Maternal grandmother when she gave birth to the mother.

Her Nuchal scan did not pick up anything and because she is relatively young it gave her a firther reduced risk.

ANyone heard anything about this?

I think I read somewhere that, although older mothers (i.e. in their 40s) have a higher chance of having a Downs baby, the higher number of babies born to mothers in their 20s outweighs their lower risk factor to the extent that that most Downs babies actually have a younger mother. (bit wordy - sorry!)

BTW, I won't be offended if someone corrects me about this - I might have remembered wrongly.

I know a girl who had a downs baby when she was 15.

More babies with Downs syndrome are born to younger mothers. The relative rate is higher in older women (they tend to have less babies over all, and more of them have downs IYSWIM)

Plus more are detected in older women since they tend to be offered more invasive and conclusive testing as their risk is, in general, higher.

I understood that LucyJu's explanation is the case.
And that because screening has been more rigourous for older mothers - and many younger mothers don't seek screening etc early in pg, that more younger women give birth to DS babies.

yes, LucyJu's and mb's explanations are right AFAIK. I know loads of younger mothers of babies with DS (this is the correct way of referring to them btw - saying 'Downs baby' is a bit like saying 'cerebral palsy child' and some parents find it offensive :)).

I think what you said about age of the maternal grandmother is just one of the vast number of unproven theories as to why a child is born with DS. There are all sorts of others - age of the father, nutrition of the mother etc., etc., none proven to be true.

I was 24 when my dd with DS was born btw, but I know quite a few mums who were even younger. Very young mums (under 18 I think) actually have a higher change than someone in their early 20s.

I think my chance based on age was something like 1:1,600, but of course someone had to be that one person. :)

yes. Nowadays more babies with DS are terminated than born. :(

She also was told that the scans are 80% accurate at predicting Down Syndrome. Se said she would have had the amnio had she been told she had a high risk but I don't know what she would have done had she had the amnio.