SMC
Ideal_Rock
- Joined
- Sep 30, 2012
- Messages
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Re: Re:
So my genetic counselor says that given my age, I'm somewhere between 1:1000 and 1:350. It's possible for my first tri screen to come back with DS risk below 1:1000 if I got some fantastic measurements, but I'm still waiting to hear back.
Shihtzulover, I know it's easier said then done, but it sounds like your doctor isn't concerned that you're at risk, so it seems like everything is ok. I think I'd like to know if the 1:800 number is based on your age or a combo of your age and your first tri screen results though.
The way my genetic counselor explained it to me is that they should take into account your NT measurement AND your first tri blood work AND your age to give you a probability. So, let's say that your measurement came back 1mm. Given all the measurements of women who measured 1mm and with your blood work profile, regardless of age, their chance of having a DS baby is 1:10000 (I made this probability up). Then they look at your age. Let's say your age is 40. A women who is 40 has a 1:100 chance of having a baby with DS. So then they combine those two probabilities together (and I'm not sure but it's unlikely that age and NT measurement are given equal weighting) and say, oh, your chance of having a baby with DS is 1:5050.shihtzulover|1406066488|3718544 said:SMC, I didn't get any true results from my NT scan except 'low risk'. I asked for the ratios and I suppose the nurse had never been asked that before. She had to go back and look at the lab results, but she wasn't really sure how to read them.
She said:
Spina bifida = less than 1 in 10,000
Trisomy 18 = 1 in 3,000 (can't remember exactly, but it was in the 3,000s)
Down's = less than 1 in 10,000, but then she said oh wait, there's another ratio here, age risk…and then it was 1 in 800 or so.
So, I'm really confused. Can anyone shed some light? Should I be looking at the first ratio or the age risk?
The nurse said the important thing is that there wasn't anything identified as high risk. 1.4mm does seem small to me, too…mine was 2mm at 12w per due date, baby measuring 12w3d. I was worried that I would come out high risk, because I also thought my HCG levels would be high.
Oh, and my practice didn't even give me any results until after the second blood draw around 15-16w (yeah, I guess I don't really qualify for this thread anymore…but it's so hard to move on!). I asked at my doctor's appointment between the two blood draws though and my OB told me that if I had been high risk, they would have stopped after the first blood draw and offered an amnio or Harmony.
I asked about Harmony, and apparently they don't offer it routinely, and they've only ordered in a couple of times for high-risk cases, but it probably would have been an option if they saw fit.
So my genetic counselor says that given my age, I'm somewhere between 1:1000 and 1:350. It's possible for my first tri screen to come back with DS risk below 1:1000 if I got some fantastic measurements, but I'm still waiting to hear back.
Shihtzulover, I know it's easier said then done, but it sounds like your doctor isn't concerned that you're at risk, so it seems like everything is ok. I think I'd like to know if the 1:800 number is based on your age or a combo of your age and your first tri screen results though.