Brown discharge at 35 weeks of pregnancy may be caused by preterm labor, vaginal inflammation, cervical polyps and abnormal placenta position. 1. Preterm labor: If the brown vaginal discharge is accompanied by abdominal hardness and pain and discomfort, it may belong to the late pregnancy irregular contractions induced by preterm labor. 2. Vaginal inflammation: the mucous membrane of the vaginal wall is stimulated by inflammation for a long period of time, resulting in congestion of the vaginal wall as well as bleeding symptoms, causing brown discharge. 3. Cervical polyps: the presence of cervical polyps in pregnant women, coupled with physical fatigue and exercise stimulation, can cause cervical polyps tissue blood vessel rupture, causing brown discharge. 4. Abnormal placenta position: If a pregnant woman has placenta praevia or placenta previa, it can cause a small amount of vaginal bleeding or brown discharge due to localized detachment. If you have brown discharge at 35 weeks of pregnancy, it is recommended that the pregnant woman go to the regular hospital as soon as possible to receive a checkup, according to the results of the treatment, do not use drugs privately, so as not to cause danger.