According to the Dietary Nutrient Reference Intake for Chinese Residents, the recommended calcium supplementation for pregnant women in early pregnancy is 800mg/day; in mid-pregnancy, it is 1000mg/day; and in late pregnancy, it is 1200mg/day. The calcium requirement of pregnant women is higher than that of non-pregnant women because the fetus needs to obtain calcium from the mother to promote its own bone and teeth development. The daily calcium requirement during pregnancy can be categorized into three stages, early, mid and late pregnancy. 1. Early pregnancy, that is, the first trimester of pregnancy, early pregnancy is the period of cell division and the initial shaping and development of organs, the recommended amount of calcium supplementation is 800mg/day, and timely supplementation of folic acid. 2. Mid-pregnancy, about 4-7 months pregnant, is the rapid growth and development of the fetus period, the daily calcium demand of pregnant women increased, the daily calcium demand of about 1,000mg, you need to eat more calcium-rich foods, such as dairy products, shrimp and other seafood, and if necessary to supplement dietary supplements, such as calcium tablets or calcium capsules. 3. Late pregnancy, that is, after 28 weeks of pregnancy, the fetus for a variety of nutrients demand more, the daily calcium demand is about 1200mg, calcium supplementation is relatively more. Pregnant women supplement calcium at the same time, must pay attention to supplement vitamin D at the same time, at the same time appropriate outdoor activities in the sun, is conducive to calcium absorption.