1. When to start calcium supplementation? Pregnant women need to start supplementing calcium in the early stages of pregnancy, because the fetal bones and teeth need calcium to build. In addition, pregnant women themselves also need more calcium to maintain the normal operation of the body. 2. The best time to supplement calcium. The best time to supplement calcium is in the first trimester, because this is when the fetal bones and teeth are developing. At the same time, the second trimester of pregnancy is also the time when calcium supplementation is needed, because the fetus has a greater demand for calcium at this time. 3. How to choose the appropriate calcium supplement product It is very important to choose the appropriate calcium supplement product. First, choose a product that contains enough