Women between the ages of 20 to 35 years who suffered from pure menstrual migraine without aura were placed into two distinct groups. The first group took 21 active pills + 7 placebo pills for three months. The second group received 24 active pills + 4 placebo pills for three months. The researchers wanted to see if the duration and severity of patients’ daily headache attacks improved while on combined oral contraception.
While both study groups showed significant reduction in the intensity and duration of menstrual migraine, patients in the group taking 24 active pills + 4 placebo pills saw a greater improvement in the severity and length of headaches compared with the women who received 21 active + 7 placebo pills…..So, for menstrual migraines, which are the most difficult to treat, oral contraceptives can stabilize and reduce the headaches (it can also go the other way, with more headaches).  Headache: The Journal of Head and Face Pain    June, 2012