I've been talking to my doctor about this problem because lately I've been experiencing the same issue. I remember one night when I broke out in tears and poor DH thinking there was something wrong with the bub. The massive leg cramp was intolerable. I found what really helped me was leg exercises during the day. Nothing strenuous. Try lying on your bed or a carpetted floor and stretch your leg in the air and then bend midway. I did them about 15 times each day and since then, haven't had any leg cramps at night! Hope this helps!