What causes leg cramps in the late stages of pregnancy?

Possible causes of leg cramps in the third trimester of pregnancy include the following: 1. Calcium deficiency: In late pregnancy, the fetus has increased calcium demands. If the pregnant woman does not supplement sufficient calcium, calcium deficiency may occur, leading to muscle spasms and leg cramps. 2. Uterine enlargement: As the fetus grows, the uterus gradually enlarges, which may compress the lower limb veins, impair blood circulation, and result in calf cramps. 3. Cold exposure: If adequate warmth is not maintained during late pregnancy, cold stimulation to the legs may cause sudden blood vessel constriction, ischemia, and hypoxia, triggering cramps. 4. Improper sleeping posture: Prolonged side-lying sleep may compress leg blood vessels, disrupt circulation, and increase the risk of cramping.