The umbilical cord is the one which is about 50cm in length that connects the baby's tummy to the placenta. It has two arteries, one is to remove waste and the other is to provide oxygen, nutrients, and blood to the baby. Once the baby is born the umbilical cord is cut, what remains is the umbilical stump. Initially, the color will be yellow and shiny, but later it changes into dark brown, purple or black color when it is about to fall off completely.
During the fall off period it may have blood stains, you need not worry but if you are profusely bleeding meet your pediatrician. Because it looks a little dirty in color does not mean that you rigorously clean or rub it. It needs gentle care. Don't ever try to pull off when it's almost dried and time to fall off. Clean it with just water and few may advise to clean with alcohol or spirits and don't do it. It will not make the healing process easy.
The complete period may take from four to six weeks. Until then it's better that the baby is given a sponge bath. If you really want to bath your baby in the tub, make sure to dry the area clean. Don't use any kind of baby products in the umbilical stump unless it's been recommended by your doctor.
It's a matter of concern only when:
I think I have covered almost all the content but any inputs are welcome.