When should pregnant women start taking calcium supplements?

The best time for pregnant women to start supplementing calcium is usually from the fourth month of pregnancy, which is the second trimester. This is because the fetus begins rapid bone development during this period, significantly increasing the demand for calcium. However, each pregnant woman's specific situation may vary, so the timing and dosage of calcium supplementation should be determined based on individual dietary habits, prenatal examination results, and the doctor's recommendations.

During the early stages of pregnancy, although the fetus's demand for calcium is relatively low, pregnant women should still ensure adequate daily calcium intake to maintain both their own and the fetus's bone health.