There is a mG forum on this website.

Bleeding issues aren't common for MG, but can be a side effect of medication she takes for her MG. does she, for example use pain killers like meloxicam (NSAIDS), or prednisone? Maybe other medication can cause this too.

Have he doctors take a close look to all the medication she is heaving or have had in the past.

Wish you the best!