 [ Symptoms ] what could cause blood in stools or vaginal bleeding two years after complete hysterectomy in 88 year old  how do i get feedback i have received nothing yet  [ Disease ] there are two ways to prevent migraine headaches 1 by avoiding factors triggers that cause the headaches and 2 by preventing headaches with medications prophylactic medications neither of these preventive strategies is 100 effective the best one can hope for is to reduce the frequency of headaches