triple screen and 20-week ultrasound

[acupuncturemomma]

Can anyone point me to good research on the false-positive rates or any other pertinent info on the triple screen? I think we'll probably skip it, but just want to make an educated decision. We need to figure it out soon, I guess, since I'm 16 weeks now...
Also, any comments or input on the 20-week u/s? We live at least 35 minutes from the hospital, and I thought it would be good to know that the babe's ok since we're planning a homebirth. My impression is that they're looking at organ formation, placenta, fluid, etc. with that ultrasound. But what is a level 2 u/s and when is it warranted? I'm 34 y.o.
THANKS!!

[KC in KS]

I'll comment on the u/s part of your question.

DH and I declined the amnio/CVS tests, though they're indicated because I'll be 35 when the babe is born. Too high a risk for our comfort, especially given the false-positive rate (I've heard varying numbers, some up around 50%. Sorry, I don't have actual stats.)

We are doing the 20-week u/s, partly because DH especially likes to see the baby - helps him believe it's real, you know. But also, we've told the doctor that if anything "unusual" should show up, we'll rediscuss our testing choices. I don't know if we'll actually do a level-two u/s; with previous pregnancy the doctor needed a "cause" to request a level-two, so the insurance would pay for it. I've heard it's standard for an over-35 mom, though.

The level two basically looks in more detail. Rather than just checking to make sure the baby's heart is there, it checks the number of chambers. That sort of thing. Here's a quick summary I found:
http://parenting.ivillage.com/pregnancy/psecondtri/0,,midwife_46h3,00.html

[ibex67]

http://pregnancy.about.com/cs/afp/a/afptesting.htm

This article indicates that there is as high as a 80% false positive. I will be almost 39 when I deliver and I declined these tests. I will have a regular u/s at 20 weeks. For me it came down to: what would I do with the info? With such a false positive rate, getting a positive means you have to follow up with more invasive/potentially risky procedures. The bottem line is I decided that I would not terminate the pregnancy based on the results of these tests. So, in that case, I could not come up with a reason to subject myself to false positives and more risky procedures. If there are issues when the baby is born -- dh and I will deal with it then. Of course, this is an intensely personal decision so there is no one right answer for everyone.

[NewAtThis]

We decided to do the triple screen test and skip the ultrasound, because we felt we wanted to be prepared in case anything wasn't ok with the baby. We have friends who recently had a baby with spina bifida (after 2 healthy babies) and they found out early enough to get into a big research study at a major hospital and had some interventions done that played a huge positive role for their baby. The study also covered all their costs. So for us, we figured if there was news we needed to know about, better to know and be prepared than be surprised, especially if it could help the baby. All the rest of my care is very low key and non-invasive, but if the tests come back positive (I find out tomorrow) then we'll probably get an ultrasound. I also have very little reason to believe anything is wrong, but it will help DH and I sleep soundly to know. As for false positives? I still think the benefits of knowing about the health outweigh the risks of not knowing. Good luck with your decision! I know it can be a hard one.

[autumnfaery]

There really is no "positive" or "negative" test results with the triple (or quad) screen. What the test results show is your risk of there being a problem. If it comes back as showing an increased risk (what some would call a "positive"), that doesn't mean there is anything wrong at all, it just means that your risk of something being wrong is higher than what would be expected for someone of your age. For example, your risk is 1/50 instead of 1/500. A "negative" just means your risk is low. Which still doesn't guarantee there isn't anything wrong. And after working in Ob/Gyn for 2.5 years and drawing hundreds of these tests on women, I saw a LOT of tests come back showing that increased risk. It was extremely rare (I actually don't really remember any, but I'm sure their were some) that anything was actually wrong. All it did was get these women good and freaked out for the rest of their pregnancy.

In case you hadn't figured it out, I'm not getting the test. I am getting the u/s though. I feel like that will actually give me some good concrete information. If there is anything obviously wrong, we should be able to pick it up.

[acupuncturemomma]

Great! Thanks, everyone, for the helpful info. We have decided to definitely skip the triple screen, but will probably do the 20-week u/s. I appreciate your quick responses.