Belly shots to prevent blood clots are usually given for about 7 days, but the specific situation should be analyzed. During the period of use to observe the changes in clotting, if effective can continue to play, if not, the doctor will switch to another drug. Belly shots to prevent blood clots generally refer to anticoagulant drugs like low molecular heparin. The most important risk of anticoagulant use is that it can cause bleeding, such as local bruising of the skin, bleeding of the skin mucosa, and in more serious cases, major bleeding, such as brain bleeding and stomach bleeding. Low molecular heparin, the half-life of these drugs are relatively short. If the side effect of bleeding occurs, the patient should stop the anticoagulant or use antagonist in time, and the bleeding can be stopped quickly, so the safety of these drugs is relatively high. In addition, anticoagulants of the low-molecular heparin class are generally applied for a short period of time, lasting no more than 1 week, and most patients have to transition to oral anticoagulants. Patients who take belly injections to prevent thrombosis should follow medical advice and check coagulation function regularly to prevent adverse consequences. Pay attention to the time of use and the site of injection, and if bleeding occurs, patients should go to the hospital surgery promptly.