It is recommended to start supplementing calcium after 3 months of pregnancy because the fetus is in the stage of growth and development during the first 3 months of pregnancy, and it will only take 3 months for it to take its first shape. The third month of pregnancy belongs to the most important period of bone development, you should take calcium supplementation in moderation, the daily intake of calcium content of about 800mg, you should take calcium supplementation through diet, you can eat more seafood. 4-6 months of pregnancy belongs to the most important period of fetal bone development, the demand for calcium increases. If pregnant women do not supplement enough calcium, it will absorb the calcium inside the pregnant woman’s body and lead to cramps. Pregnant women can eat calcium gluconate and usually pay attention to more sunshine to promote calcium absorption.