Turners syndrome diagnosed on Harmony

[fx191]

After an initial inconclusive result our second blood draw result finally came back today as greater than 99% probability of monosomy X.
All of our scans have been fine, but at our NHS appt they wouldnt do the NT measurement as they said it wasn't of any benefit if we had had the Harmony test. Has anyone any experience of this or advice? There are lots of stories of false positives on the internet but maybe I am clutching at straws....

Hello OP,

I had a diagnosis of turner syndrome following a CVS in my first pregnancy, so different to you, but I had a harmony test in a subsequent pregnancy which came back all clear. As you might imagine, I've read up on both.

In terms of accuracy, harmony tends to generate more false negatives for turner syndrome than for the main trisomies. However, I do not think it generates more false positives. The most likely explaination is that your baby has turner syndrome, and you may wish to find out more about the condition. It really is only worth having an invasive diagnostic test - amino or CVS - if you plan to end the pregnancy, as you would want to be 100% sure of the diagnosis before doing this. The nhs screening (bloods and nt measurement) are far less accurate than harmony, so pointless. That said, a common side effect of turner syndrome is the development of a cystic hygroma and fetal hydrops. This would be picked up on your scan without needing to measure the nt, and is extremely serious.

Indeed, this is why I had a CVS - because it was instantly apparent that my baby was unwell at my 12 week scan - and sadly why I chose to end the pregnancy eventually, as it was apparent that my baby would not survive to birth. The prognosis for babies with turner syndrome who do not develop fetal hydrops in utero are very good.

Given that no such issues were detected on your scan, I'd suggest taking a look at the turner syndrome support society pages for more info on the condition, and if you want to talk over the accuracy of the harmony and the other tests on the NHS you may want to call ARC.

I hope that helps. It's always a shock to find out that something is not right in your pregnancy.

The NIPT tests have a very high negative predictive value (so a low risk result is almost certain to be correct) but a postitive predictive value (the chance of a high risk result meaning that the baby has the condition) that is either a bit lower (for Downs) or a lot lower (for some of the others). I couldn't find an authoritative source for the current value for the Harmony test, so I don't want to give you false hope, but for the Panorama test I had 5 weeks ago, these values were included in the written report, so maybe you already have the information.

Thanks damesylviekrin, I dot have the specific values on my report but I have found an online calculator which works out ppv for condition based on maternal age and it seems very low for Monosomy x. Maybe I am just giving myself false hope....

@offbeatgirl Sorry to hear that you went through that. It’s not easy as my scan looked the same and not be sure what to do.

how many weeks were you during the tfmr? Which method did you use and were you able to have healthy pregnancy afterwards? Don’t know if I should just wait and see.

Sorry to hear you're in a similar position, Mimi2022. I was lucky enough to have two straightforward pregnancies afterwards, and now have healthy children. It was a one-off thing.

I had a medical termination at 15 weeks - I wasn't offered a surgical termination thorough the hospital, though I probably could have accessed one though market BPAS or Marie Stopes. I completely understand why you don't know what to do: I came to the conclusion there was no "good" or right option, just a set of options that were all bad, just in different ways. So I don't regret my decision, I just feel sad that I was in that position to begin with.