The third day of artificial insemination physiological causes of brown discharge when the temporary observation, the first sign of abortion caused by the need to pay attention to rest, temporary observation. 1. Physiological reasons: Human insemination refers to artificial insemination, which is a method of assisted reproduction technology and needs to be operated by professional physicians. When a small amount of brown vaginal discharge occurs on the third day after artificial insemination, it may be caused by the fertilized egg implantation, which is a normal physiological phenomenon and does not require special treatment. 2. Pre-eclampsia: It can also cause the symptom of brown vaginal discharge, which may be accompanied by pain in the lower abdomen. However, as the ultrasound at this time can not clarify whether it is a normal pregnancy, you can pay attention to the doctor’s instructions to take proper rest and carry out the ultrasound on time, but you need to go to the hospital in a timely manner when the symptom worsens. When there is brown discharge on the third day of insemination, you need to go to the hospital in time to find out the cause and give guidance and treatment.