Vaginal brown blood in early pregnancy may be caused by preeclampsia, ectopic pregnancy, cervical polyps and other diseases, or by other diseases such as hyperemesis gravidarum. 1. Pre-eclampsia:Pre-eclampsia is mostly caused by chromosomal abnormalities of the embryo, poor dietary habits of pregnant women and other factors. The main symptoms of patients are vaginal bleeding, paroxysmal lower abdominal pain and lower back pain, so the patients will appear in the early pregnancy vaginal flow of brown blood phenomenon. 2. Ectopic pregnancy: Ectopic pregnancy is caused by tubal disease, contraceptive failure and other factors, the patient will have irregular vaginal bleeding, lower abdominal pain and other symptoms, which will lead to the performance of early pregnancy vaginal bleeding brown blood. 3. Cervical polyps: the etiology of cervical polyps is not yet clear in the clinic, currently considered chronic inflammation and cervical infection and other factors. Patients will have vaginal bleeding, leukorrhea and other manifestations, so patients with cervical polyps in early pregnancy, there will be symptoms of vaginal flow of brown blood. 4. Other: glucose, cervical cancer, vaginitis and other diseases can also lead to the phenomenon of early pregnancy vaginal bleeding brown blood. Therefore, in the clinic, when the patient has the symptom of brown vaginal blood in early pregnancy, he should consult a doctor in time for examination, and follow the doctor’s instructions for treatment.