Brown discharge is usually a sign of impending labor, which in late pregnancy is a sign of preterm labor, but it can also be caused by vaginitis or cervical columnar epithelial ectasia. 1. Pre-eclampsia: As part of the meconium separates from the uterine wall before labor, tiny blood vessels rupture and bleed, and the blood remains in the vagina for a long time, resulting in brown discharge. At this time, you should check the fetal movement and fetal heartbeat changes. 2. Vaginitis: The vaginal discharge of vaginitis patients will be increased, yellow, yellow-green, brown and purulent, and accompanied by vulvar itching. Antibiotics such as metronidazole and tinidazole may be prescribed for vaginitis. 3. Cervical columnar epithelial ectasia: high estrogen level will lead to columnar epithelial expansion, pregnant women’s cervix will generally show the surface of the granular, touch may be vaginal bleeding, no treatment, will not affect the delivery. Once a pregnant woman has brown discharge, she should go to the gynecology department of the hospital in time to get a clear diagnosis and timely symptomatic treatment.