Menstrual cramps and pains can be treated with ingestion of Omega-3 fatty acids. It is often recommended that women get their Omega-3s from fish oil, however consumption of fish oil could potentially expose one to mercury toxicity, so I recommend instead to get your Omega-3s from hemp oil.
Hemp oil contains a 3:1 ratio of Omega-6 and Omega-3 fatty acids, which is the proper balance required by the body.
Follow directions on the bottle or as a general rule of thumb take 1 tablespoon of hemp oil per day.