Hey dont woryy, It may have to do with changes in blood circulation and stress on your leg muscles from carrying extra weight. Your growing baby also puts pressure on the nerves and blood vessels that go to your legs. And some doctors say low calcium, or a change in the way your body processes calcium, may cause cramps.. Do calf stretches before bed to prevent the cramping. ... Straighten your leg and flex your foot when you get a cramp. ... Make sure you are drinking enough fluids during the day. If cleared by your doctor, get regular exercise, which can help reduce cramps. I hope this helps