Originally Posted by unknowntoall
I will be soon taking the brand of birth control entitled Marvelon 28...I read and re-read the instructions...but I can't seem to find how long I have to take it before it is effective? A month? A week? I need to know. Thanks.
Birth Control is effecive after 7 days of perfect use. If you start it on the first day of your period though, it's supposedly effective immediately.
Many practitioners suggest waiting a full cycle before assuming that the pill is effective has a precaution.