Sudden brown discharge at 7 weeks of IVF pregnancy may be due to preeclampsia, ectopic pregnancy, cervical disease and so on. 1. Pre-eclampsia: The process of IVF may be due to maternal luteal insufficiency, external stimuli and other factors, resulting in unstable embryo development and bleeding, thus showing signs of pre-eclampsia. Pregnant women need to take bed rest and under the guidance of the doctor to carry out fertility preservation treatment. 2. Ectopic pregnancy: It is possible that the fertilized egg may be deposited outside the uterine cavity during IVF. This situation will not only cause abdominal pain and a small amount of bleeding, but also pose a threat to the life of the pregnant woman, and should be treated promptly. 3. Cervical disease: Pregnant women with cervical disease, such as cervical polyps, cervical lesions, etc., can also cause a small amount of vaginal bleeding. In the process of IVF, pregnant women should pay attention to their own physical condition, if bleeding occurs, you need to consult a doctor in time for examination and treatment for the cause of the disease.