For anyone who didn't know the morning after pills can really, really fuck with a girl's reproductive system and should not be a go to contraceptive.
Its basically a massive dose of hormones to trick her body into thinking she's pregnant to prevent pregnancy. Birth control pills work the same way but at a lower dose and requiring daily doses. But morning after puts so much into a single pill that its hard to not have side effects.
Condoms, IUDs and regular contraceptive pills > morning after.