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So worried - Down syndrome risk

(3 Posts)
Lala84 Mon 09-Jan-17 21:19:55

Hi ladies,

Firstly apologies for the lengthy post but I just gave to talk to someone about this and my husband just keeps telling me to stop worrying and all will be OK.

I am 32 years old and currently 37 weeks pregnant following IVF treatment for unexplained infertility. I posted a while back following a high risk screening at my NT scan.

At my NHS scan they gave me the following results:
NT: 1.5mm
HCG: 2.3 MOM
Papp A: 0.35 MOM

AS you can see the blood results were TERRIBLE and I should mention that the lady doing the scan really struggled to get the measurement due to retroverted uterus and in the end had to do an internal scan.

Following the scan I was given a risk of 1:109.

I was offered an amni or CVS but decided instead to visit the fetal medicine centre on Harley Street for the harmony test. The rescanned me (able to do abdominally even though just 4 days later) and unfortunately measured the NT as 2.5mm but as they take into account a number of other markers, they gave me better odds of 1:399. However, I often wonder what my NHS risk would have been if they had calculated it using the 2.5mm NT (which I believe to be correct) and not the 1.5mm!

The doctor who scanned me at FMC basically said if the harmony test came back low risk then I could forget about Down syndrome and enjoy my pregnancy. The harmony test then came back as low risk (less than 1:10,000) and I was on cloud 9. My 20 week NHS scan then arrived and all looked good, no anomalies found at all. I finally began to truly relax and enjoy my pregnancy.

Because of my low Papp A result I was told I would have growth scans from week 28. The first at week 28 went perfectly.....bubs was measuring a little above the 50th percentile across the board and all looked good. The consultant booked me in for another growth scan at 34 weeks, mainly for reassurance than anything else.

At the 34 week growth scan bubs was measuring large! 78th percentile head circumference, 95th percentile femur and 98th percentile abdomen. I was not worried about this until the sonographer told me that I also had excess fluid (Afi 21.6) and I was therefore diagnosed with polyhydramnios. Consultant didn't seem worried....she said big baby can mean more fluid. She ordered a TORCH test and GTT test to double check for infections/diabetes which can cause excess fluid. These have both since come back negative.

I stupidly googled polyhydramnios & what do you know, this is often associated with chromosomal abnormalities like Down syndrome. I freaked myself out for a bit before reassuring myself that I had the negative Harmony test and false negatives are very very rare, however I then did a bit more research into NIPT tests including the harmony test and found some rather worrying info in various studies.....

While they claim to be over 99% accurate in detecting Down syndrome, the % of Fetal fraction detected is really important. Average is 10-15%. Harmony test will not report results if Fetal fraction is below 4% but some studies have found that even if the Fetal fraction is above 4 but below 8% then the accuracy of the test in detecting downs can be reduced to about 75%!

I went back to look at the harmony test results sent through to me by FMC and my Fetal fraction is only 5.8%!!! Reasons for low Fetal fraction can be increased weight or taking the test too early but I am not overweight and took the test at 12 weeks 4 days. When the results were given to me by the FMC there was no mention of Fetal fraction being significantly lower than average or the accuracy being affected.

I am driving myself crazy.....I am so so worried that I have relied on a false negative harmony test result and now at 37 weeks feel so unprepared for what might be around the corner. My blood test results from NT scan were soooooo terrible I truly felt it was a miracle when the harmony test did come back negative.

Has anyone had any experience with a negative NIPT with lower than average Fetal fraction after a high risk NT scan?

Any words of wisdom would be greatly appreciated.

Many thanks in advance xxx

SarahOoo Tue 10-Jan-17 19:32:01

I went through the CVS back in October as we had a high risk of a chromosomal issue, our odds were 1:85 for T21 and 1:78 for T13/18. They found this due to our NT being 3.4mm and our bloods being about half of what they should be.

All in all would the result of T21 have changed the course of your pregnancy?

Ultimately for all the screening and testing they can do, something can always be not right with any baby.

I think at this stage you just need to try and say level headed, there is absolutely nothing you can do if there is something anyway.

Just breathe and look forward to that little bubba being with you x

Pestopinenuts Thu 12-Jan-17 11:44:38

OP I understand your worry and I have been worried about this myself, even though I was given low risk by NHS. I have the feeling something is wrong with the bubba and have done from the beginning. I wish now I had had the Harmony test myself as they are more accurate. But I am 35 weeks now and nothing I can do.
In my case, a DS diagnosis would have meant termination. At the time, as a first time mum I was happy with the low risk and I didnt think much of it. Now I am kicking myself for not having gone for a diagnostic test or Harmony.

I think your Harmony results are very good and I also think it is too late for us to change anything.

So we have 2 options, spend the next few week in agony or try to relax, get it in our heads that it will all be fine and see what happens.

At the end of the day, there are so many things that can go wrong in a person's life, illness, mental health, learning difficulties, an accident... We are just focussing on the chromosomal part now.

I need to try to follow my own advise OP. I want to think it will all be good at the end. Hugs

Note: I don't want to offend anyone who has DS or children with it, I know that people lead happy lives and that there is a spectrum, but I suffer from mental health problems and for me it would be very very very difficult and not fair on the child. I am also terrified of my child having MH issues like me because 80% of my life I spend in darkness.

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