My daughter is 15 yrs old and has missed her period for 4 months.. am really worried.. she has had exams?

Irregular menses: This is actually so much more common than most think. So many things can affect a teens cycle.These include weight (both too high and too low), stress, conditions like pcos, change in routine and/or exercise. Of course, pregnancy should be in the list as well. If she has been checked out and is not having symptoms, relax.Otherwise see ob/gyn that could recommend further workup and possible therapy.