Calcium tablets for pregnant women may cause constipation, mainly because the body needs a certain amount of time to absorb calcium, the calcium carbonate in calcium tablets after digestion by the gastrointestinal tract, in the process of excretion of food residues, such as oxalic acid, phosphoric acid, combined with the intestinal tract, the formation of insoluble and hard substances, making the stool dry, prone to constipation. However, the constipation of pregnant women may not be caused by taking calcium tablets, because during pregnancy, exercise is reduced, coupled with changes in hormone secretion in the body and the growth and development of the fetus, resulting in an increasing uterus, which is oppressive to the gastrointestinal tract, gastrointestinal peristalsis and intestinal tension is relatively weakened, prone to constipation. Calcium supplementation during pregnancy is essential for the growth and development of the fetus and the health of the mother. Constipation can be improved by changing the poor lifestyle and consuming fiber. Make it a habit to have regular bowel movements, be active, drink more water and eat more fruits and vegetables with high fiber content. If the constipation is serious, you need to seek medical advice, follow the doctor’s instructions to use medication, caution to use the open plug, glycerin suppositories, prohibit magnesium sulfate, enema, to avoid causing abortion or premature delivery.