Irregular periods&ovulation-no ovulation for past 3 months. cd28 now and doctor prescribed me provera (medroxyprogesterone). what if my period comes naturally when taking?

Not natural: If you start your period after taking the provera (medroxyprogesterone), (medroxyprogesterone) then it would likely not be a 'natural' period. It would b a 'withdrawal bleed' induced by the provera (medroxyprogesterone). If you don't want to get pregnant, you should take a birth control pill to prevent pregnancy. The Provera (medroxyprogesterone) will induce a withdrawal bleed and prevent over thickening of the endometrium. It won't prevent or help cause pregnancy.