Is taking Plan B too often bad for you? Causes infertility or birth defects?

Its strong hormones, so you will feel side effects. But no it doesn’t cause either infertility or birth defects, and it doesn’t stay in the body permanently, so won’t affect future fertility.

It’s not meant to be used regularly if that’s the question. If you need to resort to it often it is a good idea to step back and think about what you can do to be more responsible when it comes to prevention.