I agree that this implantation period should be treated as if you're pregnant.
I was told by my CF Dr. that continuing with Albuterol, Pulmozyme, Hypertonic Saline 7% and prenatal vitamins was safe for the baby. I discontinued Tobi because it is listed as a class D drug, very dangerous. I was also told to discontinue azithromycin.
I was told my my CNM that tums are okay if your not taking long term and no more than 4 per day. So if I were you I might consider switching to a different source for calcium; such as a Calcium/Magnesium supplement perhaps.
Good luck!!