I've used nasonex since before I became pregnant and was told there were no side effects. I have also had to use over the counter pills for allergies and acording to my pharmacist these are the ones most likely to dry up your milk supply. When I talked to my lactation consultant about it she told me that it's only a concern before you have an established milk supply or if you are having trouble maintaining your milk supply. I took the pills for a week a few month ago (my son is 9 months) and I had no change in my milk. Good luck.