Pregnant women’s blood is hypercoagulable during pregnancy, and the probability of deep vein thrombosis during pregnancy is as high as 5% to 10% in patients with a previous history of thrombosis. There are many types of anticoagulant therapeutic drugs, but the safety of drugs to the fetus limits the use of anticoagulants in pregnancy. 1, ordinary heparin molecular mass is large, generally can not pass through the placenta, no adverse effects on the fetus, belongs to the FDA certification of class C drugs. Low molecular heparin does not pass through the placenta, has no adverse effect on the fetus, and has fewer adverse effects on pregnant women than heparin, which is a class B drug certified by the FDA. 2.Pentosan sodium is a class B drug in pregnancy, and there are literature reports that it does not pass through the placenta, but the safety of pentosan sodium for pregnant women and fetus needs to be further verified. 3, bicoumarin, warfarin and other coumarin-type oral anticoagulants can pass through the placenta, early pregnancy can cause teratogenicity, late pregnancy can cause fetal microcephaly, can lead to fetal warfarin syndrome, neurological anomalies, miscarriage, preterm delivery, etc., is a FDA-approved class D drugs, prohibited in pregnancy. Heparin is not secreted from breast milk, and warfarin is protein-bound and rarely secreted from breast milk. Therefore mothers using heparin or coumadin after delivery can breastfeed. 4, aspirin may have a teratogenic effect on early pregnancy, but has not been proved, is a FDA-approved class C drug, available during pregnancy, but long-term high-dose application of teratogenicity has been reported. High-dose use of aspirin in pregnancy can lead to neonatal nuclear jaundice, 1 week before delivery, need to pay attention to its impact on the mother and child coagulation function. 5, low molecular dextrose anhydride is currently obstetrics clinical efficacy is certain, the most commonly used to reduce blood viscosity of safe drugs. However, attention should be paid to its capacity expansion to increase cardiac and renal burden and as an antigen leading to allergic reactions and other adverse reactions.