When should pregnant women start calcium supplementation?

Pregnant women are advised to begin calcium supplementation at four months of gestation, as fetal development accelerates during the second trimester, increasing the risk of calcium deficiency. Common symptoms of maternal calcium deficiency include bilateral leg cramps—particularly nocturnal calf muscle cramps—often accompanied by pain. Therefore, timely calcium supplementation, regular outdoor activity, and adequate sun exposure (to enhance calcium absorption) are essential. Calcium supplementation may include calcium supplements as well as calcium-rich foods such as dried shrimp, eggs, and pork ribs.