My period has been skipping every other month since september. What would cause it to do that and should I be worried?

Consult your MD. How old are you? Menopause or menarche. Are you on medications and, if so, what? Oral contraceptives in particular but many others can alter cycling. Family history of this or any other gynecological illnesses? Pregnant? Any other medical symptoms that have developed during this interim? Some women menstruate irregularly as their baseline - ovulating every other month for example. Stress, sleep?