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I think that there are two tests. First there is a non invasive test that can be done to evaluate if the foetus is "at risk" of Downs. Then there is a sampling
by sgt101 6y ago
I think that there are two tests. First there is a non invasive test that can be done to evaluate if the foetus is "at risk" of Downs. Then there is a sampling one that is very specific. Basically counting the chromosomes. But the catch is that the specific test carries a risk to the pregnancy - so it's not applied without cause. As well as the sensitivity issue in the article there is also a specificity issue.
My daughter was tested (non invasively) as at high risk of downs (the doctor said 50/50) we decided we didn't care... lo and behold: she doesn't have downs. I don't know enough about the area to make judgements, but I am definitely concerned that it's not a slamdunk that the doctors are getting this right.
There is a huge agenda of control around pregnancy in the UK - our consultant was so arsey about us not doing the follow-up that I had to get him changed out (it later turned out that he was struck off 2 years later for more or less murdering a woman and child, but that's another story).
- zbyte64 6y agoI think part of it is if you want a genetic sample you have to puncture the amniotic sack, which can cause complications.
- GordonS 6y agoThere is a newer type of test, only very briefly mentioned in the article, and strangely not even by name: NIPT (Non-Invasive Prenatal Testing). It works by testing tiny amounts of the baby's DNA that can be found in the mother's blood. It is close to 100% effective for detecting Down's Syndrome. It needs only a blood sample, so carries no meaningful risk for mother or fetus, but it's more expensive than the older amnio or sampling methods, so is usually only available privately (at least in the UK).
- sgt101 6y agoThanks - that's really informative, it's great that things move on.
- jmcphers 6y agoThis test is widely available in the US from e.g., Counsyl[1]. It's pretty amazing how many conditions they are able to check for with just a sample of the mother's blood; it's not just Down's but virtually any chromosomal abnormality. Our care provider strongly recommended it due to our risk factors. https://prenatalscreening.com/ https://prenatalscreening.com/