Downs Syndrome results - advice needed

[Shamoo]

Hi all, hoping for some advice as struggling to work out what we should do.

My DP is 15 weeks pregnant today, ivf baby (frozen transfer) so we know exact date. Last week we had our first nhs scan and because we were at week 14 already due to nhs delays, we could only have the blood tests for screening for Down’s syndrome; not the scan.

Results came in today as 1 in 70 risk, so high risk. We have a second blood test booked for tomorrow, privately, to look in more detail. However having been sent the results through they have done the calculations based on the baby being 14weeks5 days, due to size. We know as ivf that it was definitely 14 weeks only.
Some basic research has showed me that dating wrong can make a big difference, but I’m struggling to fully understand the data.
Does anybody know anything about this? Can we ask them to rerun the numbers based on the proper dates? What would you do? I don’t really want to pay 400 quid for another test when the dating may be all that is causing the high risk, if that makes sense.

For the one you’ve had, assuming it is the second trimester maternal serum screening test, gestation is relevant - you can ask your midwife or doctor to phone the screening service to recalculate - i believe there are online calculators but I can only find the ones for the first trimester screening tests sorry.
For the one you paid for, I assume that’s non invasive screening? That one it doesn’t matter your gestation as the test result doesn’t vary with gestation (the only thing that matters there is that you have to be past 10 weeks).
If you have had NIPS that result is much more reliable than the NHS blood test anyway so it might not be worth bothering with recalculating anyway.
Assume you had a standard scan anyway and everything is looking good otherwise - try to keep positive. Good luck

Thanks @TenThousandSpoons0 - we have only had the initial NHS blood test, which is what it is based on. We have the follow up blood test tomorrow. So fingers crossed. We emailed to ask them to update the NHS results with the correct dates but they refused. So tomorrow it is! Thanks for your reply.

Sorry I clearly misread your post, you did say tomorrow! Hope all goes well.