My 15 yr old daughter hit puberty at a normal age and began menstruating with a regular cycle. After two years of being regular her things have become erratic, often not menstruating for 50 to 70 days. Her docs say this has nothing to do with her CF as she is doing well, but I don't see how. Anyone else have anything like this happen? We could sure use some tips as her CF docs and her primary have nothing.