Magnesium and calcium can be responsible for problems experienced during menstruation such as menstrual cramps. While calcium contracts muscles and makes them tense, magnesium relaxes them. You can take calcium supplements when suffering menstrual cramps because the calcium displaces the magnesium in your body cells, and that makes the magnesium available to reduce the cramps by relaxing your muscles.
So, it is not the calcium doing the job, it is the magnesium. Have you ever felt an urge to eat chocolate at that time of month, but at no other time? Your chocolate craving could be a sign that you are deficient in magnesium, because chocolate is the one food that contains more magnesium than any other. Excess calcium in your blood can reduce its absorption, while magnesium can improve it, and your body knows this. It also knows that when you eat chocolate, its magnesium levels increase, hence the craving.
The answer is not to eat chocolate and get fat, but to eat more foods high in magnesium, such as pulses, grains, buckwheat, corn, seeds and the like. Get onto a diet rich in these and you find your chocolate craving disappears, and with it any menstrual cramps you may have been experienced. Alternatively, take a balanced supplement of calcium and magnesium, or just magnesium alone if you eat a lot of dairy products.
Magnesium is also available in supplement form. Supplemental forms of calcium and magnesium have zero calories and meating your daily requirements with zero weight gain is easily possible with dietary supplements. Look to your local or internet health food store for good quality magnesium supplements.