FTS results good but still worried-should I have amnio?

[mrsdeedee]

We were very fortunate to get excellent results from first trimester screening at 12 weeks, my risk of DS is that of a 15 year-old (I'll be 39 when LO arrives) and my combined risk of Edwards/Patau is 1 in 4301. However, my sister had a baby with Downs 2 years ago and so this is something I'm still worried about. There were soft markers although she didn't have FTS, it was diagnosed by amnio. It seems like a real risk to me this time, with my first 2 pregnancies it wasn't even on my radar.

The info on the first trimester screening test states that it detects 85% of cases of T21/13/18. So I'm wondering about the remaining 15%. If you are in that bracket what would the odds look like? Perfectly good like mine?

I feel a bit uneasy about having an amnio after such excellent results. However, I don't want to spend the rest of the pregnancy wondering if I'm in the 15% bracket. I have an appointment for the amnio in 2 weeks' time and don't know whether or not to go ahead with it. Can anyone offer advice?

I think an amnio carries a risk for miscarriage, with your kind of results if it were me I wouldn't run the risk, if you really wanted to get peace of mind you can go private and ask for a 2nd level ultrasound where the dr will check the heart etc for any markers for downs.

Tks Isabubba, I've been doing some thinking and got the calculator out since. My risk of having having a false negative from the first trimester screening is only 1 in 760. From what I read, the fact that the nasal bone was also visible at 12 weeks (although not factored into my risk assessment given by the screening) is very positive and could have my risk of an undetected DS baby as low as 1 in 2280. So I'm about 95% against having the amnio now. DH is still a bit more like 50-50. I think but we need to sit down when the kids are gone to bed and have a proper chat about it.