A healthy umbilical cord is necessary for a healthy pregnancy because it has various purposes. One of the main umbilical cord functions is to get oxygenated blood to the fetus in the womb, because the baby cannot yet breathe on his or her own. The cord then sends the un-oxygenated blood from the fetus to the placenta so that it can be excreted by the mother, keeping waste products away from the unborn baby. Another of the umbilical cord functions is the transfer of nutrients from the mother to the baby, because this is how he or she gets calories, fats and proteins that are necessary for growth. Additionally, the cord might be used after birth because it is full of stem cells that can be useful to the baby or other people in the future.
The umbilical cord is the lifeline that connects the unborn baby's blood supply to the mother's. There is a vein inside the cord that connects to the placenta, which is attached to the uterine lining, allowing blood to flow from the mother to the baby. This is how a baby gets oxygen, because the baby's lungs are not yet developed enough to breathe, and he or she is surrounded by fluid that would not allow him or her to take a breath anyway. Therefore, the baby needs the oxygenated blood that flows through the umbilical cord to the heart, which then circulates through the baby's body.
After the blood goes through the fetal body, it exits through an artery in the umbilical cord because it contains waste that needs to be taken away from the fetus. Thus, one of the main umbilical cord functions is to take the un-oxygenated blood back to the placenta, where it is cleaned. The waste passes into the mother's blood supply so it can be excreted, and the blood is left in the placenta to be oxygenated so it can be returned to the fetus. While the blood is being cleaned in the placenta, it is pumped full of nutrients, such as fats, calories and proteins, from the mother. Antibodies and vitamins are also transferred from the mother to the fetal blood, at which point the cycle starts over, with the fetus receiving the nutrient-enriched, oxygenated blood through the cord.
Though the umbilical cord is cut during the birth of the baby, many people still find a use for it. For example, one of the most well-known umbilical cord functions is as a source of stem cells, because cord blood is full of them. This means that cord blood can be used as an alternative to bone marrow transplants as a treatment for certain illnesses, such as leukemia. Cord blood also might be useful for treating blood disorders, either in the infant or in other patients. These often helpful umbilical cord functions are why some parents choose to store their baby's cord blood for future use.