Medical conditions that affect blood flow, such as peripheral arterial disease, thyroid and kidney disease or multiple sclerosis can also cause muscle cramps. In addition, certain medications may have side effects that could cause your muscles to cramp. These include, steroids, birth control pills and diuretics.
Lack of potassium and calcium in the body may also result in muscle cramps. This is most commonly found in pregnant women, whose bodies are affected by hormonal and nutritional changes associated with pregnancy.