Implantation

• Implantation is the process of a fertilized egg attaching itself to the lining of the uterine wall. For some females, this process causes a small amount of bleeding, known as spotting.
  
  

How Implantation Causes Spotting

• When the egg implants itself to the blood-rich lining of the uterus, known as the endometrium, it is connecting with the mother's circulatory system, a process which sometimes causes minor bleeding, according to the website Babies Online.
  
  

Time Frame

• According to the American Pregnancy Association, implantation and the spotting that follows usually happen 6 to 12 days after fertilization.
  
  

Duration

• Implantation bleeding is different for everyone. The light spotting can last from a few hours to a couple of days, according to the American Pregnancy Association.
  
  

Appearance

• Spotting from implantation is usually dark red, brown, or light pink, and is much lighter than the flow of an average menstrual cycle.
  
  

When It Might Not Be Implantation

• According to the website Babies Online, spotting is usually not a sign of implantation if it is bright red. Also, bleeding that can be categorized as a flow, or that is similar in volume to a regular menstrual cycle, is likely not implantation.