Low molecular heparin calcium is an anticoagulant drug that belongs to the heparin class and has a lower molecular weight than heparin, hence the name low molecular heparin. Its effect is mainly for the inhibition of coagulation factors to achieve the effect of anticoagulation, and it can be used for patients who have thrombosis or prevent thrombosis. The therapeutic amount of low molecular heparin calcium, which is 100 IU per kilogram of body weight, needs to be calculated according to the kilogram of body weight. It is injected once every 12 hours, by subcutaneous injection. For prophylactic dose, it is 2500-5000 IU, which is injected only once a day, also subcutaneously. For the complications of low molecular heparin, which can lead to thrombocytopenia, osteoporosis and abnormal liver function, calcium low molecular heparin is not able to pass through the placenta, so pregnant women can safely use it, and there is no great impact on the fetus on pregnant women.