How Long Can Anti-androgen Pills Be Taken For Amenorrhea?

good day! my fiancee has been taking anti-androgen pills for more than a year now, it was meant for her amenorrhea... but since she started taking them she hasnt went back to see the doctor... im worried that this is no longer safe for her, she's only 25...and could this affect our future plans of having a baby? please help, i really want to know how long should you usually take these pills for amenorhea?...thanks