After you give birth, either via cesarean birth or a vaginal birth, you will bleed from your vagina. The cause of this bleeding is the healing of the uterus, specifically where the placenta was attached to the uterine wall. As the uterus slowly shrinks back down to nearly it's prepregnancy size in a process called involution, the body expels blood form the wound inside.
The first few days after you give birth you can expect to see more blood than you would normally see in a heavy period. This can also include blood clots. Though the amount of bleeding will diminish each day. The first time you stand up after giving birth, you may actually have blood run down your legs. This is because when you sit or lay down, the blood pools in the vagina.
You should not use tampons for bleeding after giving birth as this might cause an infection. It can also irritate the vagina if you had a vaginal birth. It is recommended that you use maternity pads or something similar. Some women choose to use bladder control pads or adult diapers for the first few days because of the heavy flow.
If you experience bleeding that soaks a pad every hour for two hours, you should call your doctor or midwife as it may be a sign of postpartum hemorrhage. Blood clots are normal in the first few days, beyond that seek advice from your practitioner.
Your bleeding will eventually taper to a normal period and then to spotting. The color of the flow will go from bright red, to brown to a yellow or whitish color as your uterus heals. It is normal to see an increase in amount or a darkening of the color of the blood if you do something more strenuous or move around more. This may be an indication that you need to take it easy.