I've been on ortho tri cyclen for about three years now and I've always had a regular normal period. My husband and I have continously had sex with no other forms of contraception for these 3 years. But 3 months ago in January I had a dark brown almost blackish stringy slime for the entire 6 days that I was suppose to get my period. Went to the GYN everything was normal and I wasn't pregnant. My periods for feb. and Mar. was regular normal periods and now for april I have the same dark brown stringy slime in place of a normal period. Is this normal? Does the birth control play a role? What causes this to happen? Why now after so many years of using the pill?