Bleeding in the fifth week of pregnancy may be caused by preeclampsia, ectopic pregnancy or cervical disease. 1. Pre-eclampsia: Generally speaking, five weeks of pregnancy is still in the early stages of pregnancy, this time the embryo has not yet been stabilized, so if you are too tired or traumatized, etc., may lead to the phenomenon of pre-eclampsia, resulting in vaginal bleeding symptoms. 2. Ectopic pregnancy: If the fertilized egg does not settle in the uterus, it may lead to ectopic pregnancy, and if there is ectopic pregnancy, it will also lead to abnormal vaginal bleeding. 3. Cervical lesions: Excluding abnormal development of the fetus itself, cervical diseases may cause bleeding, which in turn causes vaginal bleeding symptoms. Therefore, if you have abnormal bleeding during pregnancy, it is recommended that you consult a doctor in time for symptomatic treatment.