Seeing red at 35 weeks of pregnancy may be caused by preterm labor, placental abruption, placenta praevia, cervical disease and so on. 1. Preterm labor: If you see red vaginally at 35 weeks of pregnancy, and if you experience contractions within 24-48 hours, you may be experiencing preterm labor, and you can decide whether or not you need to undergo fertility preservation treatment based on the condition of the fetus. 2. Placenta previa: the placenta is detached prematurely due to external trauma, etc., and the pregnant woman will experience vaginal bleeding, accompanied by abdominal pain and other symptoms. 3. Placenta praevia: when the placenta of a pregnant woman covers or reaches the opening of the cervix, the pregnant woman will experience painless vaginal bleeding, which can be clearly diagnosed through ultrasound examination. 4. Cervical disease: pregnant women with cervical polyps and other cervical diseases due to hormonal stimulation in the body may also experience vaginal bleeding. Vaginal bleeding at 35 weeks of pregnancy requires timely medical examination to clarify the cause of the disease and treatment under the guidance of the doctor.