Umbilical cor blood up to 180mL of blood from a newborn baby that is returned to the neonatal circulation if the umbilical cord is not prematurely clamped. In some obstetric and midwifery practices, physiological extended-delayed cord clamping protocol, as well as water birth, allows for the cord blood to pulse into the neonate for 5-20 minutes after delivery. If the umbilical cord is not clamped, a physiological clamping occurs upon interaction with cold air, when the internal gelatinous substance, called Wharton's jelly, swells around the umbilical artery and veins.