Hi there. I'm trying to follow your post . . . your friend has not had sex recently but four years ago? Sperm can live for about a week. :>) Irregular periods are pretty normal especially in the teen years. Nothing to worry about even though it is annoying. good luck
I don't think so. She had her period. It's fine! But that she has irregular period, because of body problems,, i mean hormones! If they just started its okay to be irregular for a year! But if they are not going to stabilize then she need to go to doctor to stabilize them!