Fetal Fraction at 21 weeks
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Anonymous
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I'm a high risk pregnancy due to recurrent miscarriage with trisomy, PCOS, and hypothyroidism. Instead of the traditional second trimester screening, I opted for the MaterNiT21 test. Thankfully, the test came back negative for Trisomy 21/13/18. The odd thing is, my fetal fraction was only 7%. That seems low for 21 weeks gestation. I understand it is high enough to be accurate for the trisomy screenings, but the actual fraction seems like it should be higher.
I'm not overweight. My check up the other day revealed a heartrate of 153, normal blood pressure, normal thyroid levels, normal glucose levels, a normal fundal height, I've gained 12lbs since pre-pregnancy, and the baby is kicking away. I take 112mg of Synthroid and 1000mg of Metformin each day. Perhaps I'm just worried due to my previous pregnancy losses. Does my fetal fraction mean anything? |
Anonymous
| Are you the anxious chick who was posting about being one day off on her EDD for her AFP test? |
Anonymous
| I did not take the AFP test. I decided to take the MaterniT21 screening due to its high accuracy rate for Trisomy. I've had two confirmed Trisomy miscarriages and IUGR. |
Anonymous
It doesn’t quite sound like that poster, who I don’t think had a history of loss to up her anxiety... |
Anonymous
If it’s high enough to be accurate according to the lab, don’t worry. I don’t even have any idea what the average fraction is. Try to relax. Congrats! |
Anonymous
It’s really starting to get annoying how anyone is anxious about anything, people assume it’s one person |
Anonymous
Thank you for the response. Honestly, I can't find too much info on average fetal fractions. After receiving my MaterniT21 report, I saw fetal fraction on it. I googled what that was. I saw most ladies who were only 12-14 weeks with higher fetal fractions. My losses coupled with my health issues has me over analyzing everything it seems. |
Anonymous
I feel you but that test is really accurate so take comfort in that. I guess there’s no 100% unless you get an amino but that has its own risks. I’m a bit like you in that my cell-free DNA test was also good but I’m not *completely* reassured. I’m at GW MFA and don’t get any print-out of results — the genetic counselor just called me and said the test found to evidence of abnormal chromosomes. (It’s a slightly different test than MaternitT21.) There’s no fine print or fractions for me to pore over and second-guess. I was annoyed at first but it’s probably for the best. I’d do the same thing you are! Anyway, this is a long way of saying you’ve gotten a really high degree of reassurance (think of the unknowns are mothers dealt with!) so try to be happy. |
Anonymous
| ^^^ NO evidence of abnormal chromosomes |
Anonymous
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^^^ our mothers
Ugh with the typos — I have a weird problem of mixing up phonetically similar words when I type! |
Anonymous
Is it annoying because you are them? The timing for how far along she was is similar to OP and to be fair to PP, that poster was ridiculous. |
Anonymous
Yeah the over-obsession with diagnostic tests seemed similar to me. Sorry, OP. I'm sure as long as the sample is within the labs tolerance then your baby is fine. |
Anonymous
| Why are you being tested so late? This test is usually offered much sooner. Is this a retest? |
Anonymous
I was going to ask that too. I didn't even know it was administered this late. OP, is there a reason you didn't have this test done at 11-13 weeks like usual? |
Anonymous
| hmmm... my test didnt work at 11 weeke because of the low fraction. I don't know how much it was but I from the readings it seems that the average was around 13-14% (at the end of 1st semester) and what worries me even more, the proportion of defects is higher among those cases where the test didn't work. it seems that low FF does correlate with something bad but it's far from 100% or anything. |