i am 44 yrs old i did not have my period for a few months and i am not pregnant .I started progyluton in year 2009 November for just once and the period comes monthly for 9 months but stop after that. i was then prescribed again but not taking monthly. I take it every three months. That means my period comes only every three months . Would like to know weather should i take monthly? or quarterly? Doctor please advise . Thank you so much.