Brown discharge during pregnancy may be caused by miscarriage, fetal arrest or gynecological inflammation, which need to be analyzed specifically. 1. Pre-eclampsia: brown discharge during pregnancy may be caused by pre-eclampsia, when the embryo is unstable, leading to the separation of the sac and the uterine lining, which in turn leads to small amounts of vaginal bleeding, brown discharge. 2. Fetal termination: If the embryo has stopped, it may also lead to the appearance of brown vaginal discharge, usually accompanied by abdominal pain and other abnormal symptoms. 3. Gynecological inflammation: vaginitis, cervicitis, cervical polyps, etc., may also appear in a small amount of vaginal bleeding, the blood accumulated in the vagina for a long time will turn brown. Brown discharge during pregnancy may also be caused by other reasons, it is recommended that once the patient found their own vaginal brown discharge during pregnancy after the flow, timely access to improve the relevant examinations, standardized treatment.