In the 5th week of pregnancy, if there is brown discharge, it is mostly seen in the following cases: 1. It is because the fertilized egg is in the bed, some women may have a small amount of vaginal bleeding during the fertilized egg implantation, this is because when the fertilized egg is implanted in the endometrium, it will destroy the small blood vessels, there will be a small amount of vaginal bleeding, but this vaginal bleeding will be completely clean in 1-2 days. 2. In this case, ultrasound will reveal a gestational sac in the uterine cavity, but the progesterone level may be slightly low, and this symptom needs to be treated with progesterone to supplement the progesterone level. 3. If the ultrasound does not reveal a gestational sac in the uterine cavity, a blood test for HCG will be taken and the ultrasound will be repeated 3-5 days later to rule out ectopic pregnancy.