The most common causes of leg cramps in pregnant women are as follows:1. Due to calcium deficiency, due to the increased demand for calcium during pregnancy. If pregnant women do not pay attention to calcium supplementation or do not often sunbathe, it may cause calcium deficiency in the body and thus cause leg cramps; 2. Stimulation can also lead to muscle cramps. In short, the most common cause of foot cramps in pregnant women is calcium deficiency, so attention should be paid to calcium supplementation. The second is cold, so you need to pay attention to keep warm.