Brown discharge can be either implantation or menstruation, depending on when it occurs and how much. A small number of women will have a small amount of bleeding when the pregnancy is implanting, mainly due to the fertilized egg invading the uterine lining during implantation, causing a small amount of shedding of the uterine lining. This bleeding is usually small in amount and mostly occurs about 7 days after conception. If the brown discharge occurs 7 to 10 days after the day of ovulation, consider it to be implantation. If the brown discharge occurs more than 14 days from the day of ovulation, consider it to be the onset of menstruation, and the bleeding usually increases gradually on the 2nd or 3rd day. If you can’t tell whether it is implantation or menstruation, you can go to the hospital to have a blood test to check the level of human chorionic gonadotropin to make a clear diagnosis, or you can wait until the brown discharge disappears and use a pregnancy test to detect it.