no. it happens to me. I was on lo lo loestrenfe for over a year and didn't get a period. I switched to depovera, had my period for 2 weeks. then I switched to mirena, again no period. my gynecologist says that its the type of hormones they use and dosage. so its possible to not have a visual period. and I mean visual because according to her, even if you saw a spec of blood (size of a ball point pen tip) that's your period for the month.