Edited by withlittlelungs - 9/26/12 at 8:57am
I have two very different heartbeats when I listen with my doppler, one on the left and one on the right. The baby on the right is in the back, so it takes a while to find it, but yes, I think if you took time to listen and moved all around you would be able to tell
At 11 weeks, I couldnt tell the difference. In fact, I think it was about 13 weeks before I could tell the difference, and that was only because I had just had an ultrasound appointment and I knew exactly where they were. Even then, it took me 15ish minutes to find both heartbeats with my sonoline B. About two weeks ago I was freaking out about not feeling any movement and checked on them and I found Baby A instantly, and it took me a bit to find B's heartbeat. Now at 20 weeks, I still have to search around for Baby B's HB. If I wasnt sure she was in there, I'd never hear it, because it's always in a weird place.
Is there some reasoning for not getting a us? I thought most anti-us people were in the camp that dopplers were even worse than us because they emitted even more waves per second than ultrasound does. Personally, if I thought it was twins, I'd want to know for dietary purposes and to find out if they di/di or mono/di or mono/mono. Different types of twins have different risks and I'd need to be aware of those (especially with mono/mono)
Do you know how to measure? When I was 15 weeks (thats what your siggy looks like) I was measuring about 21-22 weeks along, and I typically measure small.
I was measuring 20 weeks at my 16 week apt., and my MD tried using two dopplers to see if she could find two different HBs at once. The idea is that sometimes you find one, baby moves and it's HB might change slightly, and you can't be sure that the second HB you find is the same baby or a different one (unless they happen to be very different). She found one and had my DH hold that one still and turn down the volume while she searched for a second HB with the other doppler. She did find another HB, but the baby (or babies) was being too squirmy to keep track of it long enough to compare the two. The brief listen we had of the possible 2nd HB wasn't enough to tell if it was the same one or not. Once the babies get bigger it's easier to tell if the two HBs are coming from different locations. I'm getting an anatomy scan this friday and we'll find out for sure then.
Measuring large could just be the way you're built or whatever, but I think the benefits of making sure everything is o.k. in there outweigh the small risk of u/s. The studies that show some possible risk from frequent u/s are about frequent EARLY u/s. You're past that risk period now. Before this pregnancy I was on the fence about getting any u/s, even the 20 week anatomy scan that many doctors and midwives require, but measuring large seems like a good enough reason to go ahead and do it. I NEED to know if it is twins or not, and if it's not, I want to make sure that it's not excess amniotic fluid, which could be an indication of gestational diabetes or complications with the baby. There's also a chance that you had a period when pregnant and are a whole month further ahead than you thought. That's very unlikely for me, since I was charting and it's pretty clear when I ovulated, but if I were a month ahead I wouldn't want to go into labor what seems like a month early and think the baby is coming out premature and be treated as a high risk delivery, etc. etc.