Hello. As you know, Primolut is a progesterone-like hormone that disrupts your normal menstrual pattern. The period that follows a course of Primolut can vary quite a bit, depending on where you are in your cycle when you take the medication and how long you use it. Additional variables, such as stress, exercise or other medications, can also influence your menstrual flow. Thus, every period that follows a course of Primolut won t necessarily be the same. If you had unprotected intercourse around the middle of your last cycle, it would be prudent to take a pregnancy test, as pregnancy would obviously alter your pattern of menstrual bleeding, too. (Many women experience vaginal bleeding during the first few weeks of pregnancy; about half of women who experience early bleeding go on to have miscarriages.) If you re not pregnant, your usual menstrual pattern should resume within a cycle or two: your upcoming cycle should be roughly the same length as your normal cycles. If your pregnancy test is positive, see your OB/GYN to begin prenatal care. Good luck!