The umbilical cord and placenta are thrown away in the West, but elsewhere they have supernatural powers and form the basis of birth rites in many cultures.
Once cut, the cord is often buried with a sapling such as a coconut, palm or avocado tree. The umbilical cord is nourishing, and the state of the tree's health as it grows is said to depend on the baby's state of health. Another custom involves keeping the umbilical cord as a kind of good luck charm.
In India and Mexico, the cord is placed around the child's neck, while in Turkey it is kept in the house. In other societies, the umbilical cord is eaten, either to treat colic or to strengthen the bond between the newly-extended family.
Some ethnic groups think of the placenta as the baby's twin, so rites are performed to preserve and control the supernatural link between them.
In Mali, it is thought that the placenta can affect the baby's mood or even make him ill. The placenta is washed, dried, placed in a basket and buried by the father.
In Cambodia, the placenta is carefully wrapped in a banana tree leaf, placed beside the newborn for three days and then buried.
In some regions of South America, Korea and Reunion, the placenta is burned after birth to neutralise it.