Prethrombotic state, also known as prone to thrombosis, is a hypercoagulable state of the blood caused by autoimmune diseases. It may not only cause systemic thrombosis, but also may cause the formation of blood tethering in the uterine placenta or umbilical cord during pregnancy, resulting in multiple early spontaneous abortions and even late intrauterine death. The main tests for pre-thrombotic states are β2-glycoprotein, antithrombin III, antiphospholipid syndrome, and antiphospholipid antibodies. If the results of these tests are abnormal, pregnant women who have had more than two spontaneous abortions or unexplained intrauterine death should be given prophylactic anticoagulation with low-dose aspirin and low-molecular heparin to avoid recurrent spontaneous abortions, embryonic abortions, and unexplained large-trimester fetal death.