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Pregnancy

Talk about every stage of pregnancy, from early symptoms to preparing for birth.

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Original poster

20 week scan

8 replies

SassySpain · 07/07/2007 16:40

Hi
Just had my 20 week scan. All fine as far as can be seen, but how reassuring should that be? Dh is still concerned because a few weeks ago when we got the blood screening test results although overall result was good(1/620) one level (hCG) was high and the gyn referred us to an amnio doctor. The specialist advised against amnio based on low risk overall result so we didn't have it done.
Now dh confesses it's made him worry about the possibility of Downs Syndrome and he can't get it out of his head.
Does anyone know how effective the 20 week scan is at detecting anomalies? Has anyone had a similar experience?

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jabuti · 07/07/2007 16:43

hi sassy,

as far as i know, the 20 week scan does not check for syndroms (down, edwards...). for that you need the nuchal fold scan + blood tests, that is usually done around 12 weeks.

but wait and see what the other mumsnetter have to say about it, i could be wrong.

AnnainNZ · 07/07/2007 17:51

Hi Sassy

They do look for physical signs of chromosomal abnormalities at the 20 wk scan. I had mine 3 weeks ago (after getting low risk results from nuchal fold/blood tests 1 in 2000+) and they found calcium deposits in the baby's heart that can be a marker for Downs (but can also mean nothing at all). I had a further scan a week later with a specialist who looked for any other signs. There were lots of other things she looked for, in the brain, heart, bladder, kidneys, placenta, spine and probably other places that I can't remember now. Anyway, no other signs were found and my risk of the baby having DS was revised back down to 1 in 2500-3000.

As far as I know, the scan is not 100% efffective in diagnosing Downs or anything else, but there is a good chance that some sign would be picked up from it.

Chooster · 07/07/2007 19:51

Hi,

There are plenty of people who will know more about this, but as has been said the 20 week scan will show any markers for the symdromes if they are present.

Generally I think the 20 week scan is as good as it gets scan wise. In a previous pregnancy (am now 38wks) my baby was diagnosed as having a fatal genetic abnormality. It was confirmed at the 20 weeks scan. In this pregnancy I had lots of scans to ensure the situation hadn't occured again. After the 20 week scan (where everything looked fine) I was advised that I didn't need any more scans as there was little point as by 20 weeks pretty much everything is formed and if a problem can be detected then they should find it by then. Did you have a nuchal scan? Perhaps it may be worth asking for more information on what could cause a high hcg level????

Good luck with your pregnancy and I hope your worries soon pass.

Original poster

SassySpain · 07/07/2007 22:42

Yes, I had a nuchal scan which was very low risk (1.3 mm) which added to the final result of the blood screening (nuchal + hCG + PAPP + mother's age + gestational age) which was low risk. It was just the irregular hCG on its own that caused the gyn to refer me re amnio. I've read that a high hCG at that stage of the pregnancy CAN be an indicator of Downs but on its own the amnio specialist didn't think it was enough of an reason for amnio.

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Chooster · 07/07/2007 23:00

It could be that there are other reasons for the hcg level - or perhaps just one of those things that can happen. 1.3mm is a very low nuchal measurement, so it sounds that you've got some good results there. But I do understand that once you've got something in your head its difficult to get rid of it. Perhaps a chat to the mid-wife who may be able to provide some more concrete advise?
x

eidsvold · 07/07/2007 23:20

very effective as my dd1's heart defect and down syndrome was detected at her twenty week scan and again after a fetal cardiac scan.

Her heart defect is what is termed a 'hard' marker for down syndrome. In fact it would have been very rare had she been born with the heart defect and without down syndrome. She was born with down syndrome and of course her heart defect - which was repaired with two open heart surgeries when she was 8 weeks old.

With dd2 - they found a 'soft' marker for down syndrome - calcium deposits in the heart - these deposits are found more and more often as equipment becomes even more sophisticated. However in dd2's case it just increased my risk rather than being a hard marker which is more indicative. Dd2 was not born with down syndrome.

Why is your husband so worried about Down syndrome??

Original poster

SassySpain · 08/07/2007 00:07

He's worried just because of the uncertainty the obstetrician put in our minds. Here in Spain you don't just get a result for the first trimester blood screening in the form of 'positive/negative' or 1/x risk (high or low), you see each individual numerical value for the hCG, PAPP, nuchal translucency etc. So when someone you trust circles one particular value and says he'd recommend amnio, even when you go to the next stage and the specialist advises against it you still have that nagging worry at the back of your mind I suppose.
Even he says it's irrational based on what we've read, but that doesn't mean you forget it totally.

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maisym · 08/07/2007 01:18

it's all just risk factors - amnio has a risk of around 1 in 200 of miscarriage - your blood test gave a risk of 1 in 620 of downs.

Usually the scan would check for probs. When I had my scan they checked everything they could but said that only an amnio would show absolutuely if things were all ok or not.

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