Have her take a pregnancy test first of all. It could just be normal. For some reason women sometimes have a longer cycle esp if they are under stress, exercising, or have a weight loss/gain. I would say though to take a test first. If that is negative then she should call her doctor because they may want to confirm that negative result with a blood test. They may also want to check a few other things like her thyroid and hormone levels. I think using protection all the time is a good thing esp if you do not want kids yet. Sometimes women ovulate sooner or later than expected due to the above listed things as well. Good luck and I hope everything works out ok for you.
well it might be too late. since her period is late ask her to take an hpt.