12 week screening tests with twins - not sure what to do

[QueenOfThePumpkins]

Hi everyone,

I've got my 12 week ultrasound on Friday and have known for a couple of weeks that we're having identical twins (early private scan).

We had initially planned to have the combined testing for Down's, Edwards' & Patau's, but yesterday I learned that it can be very inaccurate with twins. So now we're not sure what to do! I've read that there is a higher chance of a false high risk reading with twins, so then there could be the decision about the more invasive testing. My twins are currently thought to be the rare and risky MCMA type so I don't really want to chance anything else that could be risky (apparently there's up to a 1/50 chance of the invasive testing causing miscarriage with twins). Can anyone else who knows about this stuff, or has got twins and been through the decision, offer any advice please? I know it's totally mine and DH's decision to make, but we are incredibly unsure at the moment and don't have that long to think about it.

I don't really know, but can you have a nipt test with twins?

I had the screening with my twins - it came back normal. Obviously there are two parts to the screening - the measurement of the nuchal fold on each baby, and then a blood test where they measure certain hormones in your blood. I suspect this second part is where any false positives may occur.

You could go ahead and then, if a risk shows, opt for the NIPT blood test privately. This will tell you whether either baby (or both) has these conditions, and you could then decide whether to have more invasive testing.

It’s a difficult decision, and I suppose it largely depends on what you would do if the result showed something.

MCMA pregnancies do carry more risk than DCDA pregnancies, but because they have separate placentas you don’t have to worry about twin to twin transfusion syndrome which is good :)

I hadn't thought about NIPT - off to do some reading about that now! Thank you very much

I didn't have twins but I have had pregnancies after recurrent mc and in that context the (lower) risk of mc after amnio was not acceptable to me. But we didn't have any screening either, beyond scans (more of those than you would get in the UK, though).

IIWY and testing was important to me in principle, I would get a NIPT done if possible. In your situation I think the mc risk would seem too high to me.

Our id twins are now 11, so things might have moved on, and it might be more reliable now, but we wished we hadn't done the screening. We didn't realise until afterwards about the potential for false positives- noone told us at the time. We had it without thinking as we were offered it and were in such a daze about finding out we were expecting id twins we didn't think it through. One of ours came out as 1 in 11. We wouldn't have done anything if they had had ds or other conditions so we didn't take it any further. Even though we knew if one had it, they both would. At subsequent scans they could see there were no heart problems or other obvious markers and we had since read up about the unreliability so we put it out of our mind to a certain extent. All was fine in the end - but it was worry we really didn't need at the time. The good thing for you is you've got time to make an informed choice about whether or not to have it or another test beforehand. Good luck- hope all goes well.

Where are you? If you can get to the Fetal Medicine Centre on Harley St I would get an appointment with Prof Nicolaides and take advice. He is wonderful. He devised the nuchal scan, is probably the best fetal medical expert in the world and specialises in multiple pg’s (Does incredible in utero surgery). The clinic is run as a charity so isn’t £££.

I had NIPT test for twins at 10 weeks. Several of the brands are still highly accurate (like 97% plus) and you can still get the nuchal check as extra reassurance. My risk came back very low for all 3 trisonomies and subsequent nuchal check and anatomy scan all good. The only downside is it's expensive (£3-400) but it's just a simple blood test, not at all invasive and zero risk to the babies.

Thanks so much for your responses, everyone.

I'm sorry to hear about your experience @inmyplace, that sounds really stressful. I'm glad that it all worked out in the end, but it's a shame about the unnecessary worry.

Having looked into the NIPT test and weighed up the responses here, we decided to go ahead with the NHS screening, with our minds very much open to the fact that it may come up as high risk. If that happens then we will go for the NIPT, and not the more invasive tests unless that also shows concerning results. It sounds fairly common to get higher risk results with the NHS screening and then low with the NIPT.