Compared with adults, all babies have very low levels of vitamin K in their bodies. Without vitamin K, blood cannot clot normally and the baby can develop a tendency to bleed easily. In some cases, this leads to serious bleeding from the stomach, umbilicus (navel) or intestine (gut) and in a few cases to bleeding in the brain. This condition is called Vitamin K Deficiency Bleeding (VKDB).
Studies show that in babies who do not receive vitamin K, the risk to the baby of developing VKDB is one in 10,000. However, it is not possible to predict which babies are at risk of bleeding. We do know that this potentially dangerous condition can be reduced by giving the baby vitamin K after birth.