Could The Continuous Bleeding In A 13 Year Old Be Due To St. John's Wort?

my 13 year old has just started taking birth control pills as a safty measure and has had a period continuously for the last month. her doctor switched her from Ocella to Yasmin but she is still bleeding. She has a form of autism which she takes St. John's wort to help with keeping her on an even keel. Is there any kind of birth control pill that will work with her st. john's wort and could this be the reason for the continuous bleeding?