I went for my amnio Tuesday. They told me that the fluid behind the baby's neck was "resolving." They didn't give me a measurement, but it was much smaller Tuesday (at 15 weeks) than it was at 13 weeks. The amnio itself was much faster and less uncomforable than I expected. I spent yesterday just lying around for 24 hours, as they advised, and now begins waiting the long 10-14 days for results. We opted not to get the FISH results (which can come back in 24-48 hours), as they said those aren't very accurate at detecting or ruling out Turner's, and that is what my doctor was originally leaning towards as a diagnosis. I don't want to deal with any false positives or negatives; I'd rather just wait it out and get sure results.
The ultrasound showed the baby is continuing to grow at the expected rate, and the heart rate is normal. So I have that good news to hold on to for now.