I have endometriosis and not one month is a normal period i bleed through the pills even pills to stop the bleeding i have curently been bleeding 30 days and it is almost black blood. what is the cause.

Endometriosis ?'s: Endometriosis by itself will not cause prolonged bleeding. If you are taking oral bcp's, they should be taken punctually (w/in one hour of the prior pill, as the amounts of hormones these days is very low, and withdrawal bleeding can occur similar to the onset of menstruation, only persistent since continued taking of the bcp's will not stop the withdrawal bleeding from estrogen levels dropping.