My daughter is about to be 17. she can not have a period without birth control. can this be harmful if she never has a period?

Find out why: Not having a period indicates that the body is sending a message--and figuring out why there's no period is key. Your daughter should have had some hormone tests done to sort out why she's not having a period. After that, the pills may be helpful in treating the underlying problem, but it's best to know why she has the problem before treating it.