Congestive cramping is usually characterized by a dull ache in the low back or pelvis, often accompanied by bloating, breast tenderness, headaches and irritability. With this type of cramps, restrict salty foods since they increase fluid retention. Also, food allergies may contribute to the problem. Several supplements are beneficial. B6 also assists in the formation of beneficial prostaglandins.
Magnesium supplements help prevent muscular contraction.
Besides that, I recommend muscle-relaxing herbs such as dong quai and cramp bark. Diuretic herbs such as dandelion, nettle and uva ursi can alleviate fluid retention and bloating. And, ginger and Ginkgo biloba improve circulation to the pelvic region and help widen and dilate the blood vessels. I can't overemphasize the need for getting essential fatty acids in the form of flaxseed oil, pumpkin seeds, fish oils, or by eating cold-water, fatty fish such as tuna, salmon, trout or mackerel. In general, exercise promotes pain relief and prevention of menstrual cramps.