amenorrhea
"I have taken Provera once before to help regulate my period. My menstrual cycle is very irregular (I can go up to 6 months between cycles with some cycles lasting up to 3 months) and it seemed to have worked after the first time taking it. However, after six months or so my periods became irregular once again. I've just started taking it for the second time and it seems to be working, although I will have to say it's given me some pretty intense mood swings."