Congrats!! I am 31 weeks pregnant and have been using Pulmozyme throughout my entire pregnancy. My high risk obgyn and my CF doctor both said it is safe to take while pregnant and I haven't had any problems. I am also taking Zithromax 250mg MWF, and inhaling Xopenex 2-3 times a day. I have inhaled Colistin when I felt myself getting sick - and when that didn't work, I went on IV meds (Aztreonam and Zosyn, both category B drugs while pregnant) and am actually going back on IV tomorrow because the MRSA & Pseudomonis are back, my cough is getting bad again and my sputum is nasty! Somehow though, my PFT's are still great - best they've ever been in YEARS - they're at 80%! I guess because now that I am pregnant, I am taking care of myself better than I ever have before. Usually, pre-pregnancy, my PFT's were always low 70's, even 69 last summer.
Oh, I use the Flutter also - I have never been a big fan of the vest... I have it, but it just collected dust in my closet and I tried it when I was 12 weeks pregnant and hated it even more lol! So I use the Flutter twice a day.
Good luck! Congrats again!