How far along are you when implantation bleeding starts?

Implantation bleeding usually occurs 10 to 14 days after conception, which is about the time when the fertilized egg implants into the lining of the uterus. The bleeding is typically light and lasts for a few days, but it can sometimes be mistaken for a period. If you are experiencing implantation bleeding, it is important to see your doctor to confirm that you are pregnant.