Inorganic calcium tablets. Common are calcium carbonate, calcium hydrogen phosphate, calcium chloride and calcium oxide. Inorganic calcium tablets have high calcium content, but low water solubility. After entering the body, it must be dissociated into calcium ions through gastric acid before it can be absorbed and utilized by the human body. Some pregnant women who take this calcium tablet may have gastrointestinal irritation symptoms.

Calcium organic acid tablets. There are mainly calcium gluconate, calcium lactate and calcium citrate. Most organic calcium tablets have low available calcium content, but their water solubility is better than that of inorganic calcium tablets, and their irritation to pregnant women's gastrointestinal tract is relatively small.

Organic calcium tablets and milk calcium are ideal calcium supplement products. Organic calcium tablets are the third generation of calcium, and milk calcium is the new generation of calcium. Extracted from milk, it is easy to be absorbed naturally and has little stimulation to gastrointestinal damage.