Stem cells from umbilical cord blood are hematopoetic stem cells (like adult bone marrow stem cells), meaning that they make blood cells. Receiving a cord blood transplant is similar to receiving a bone marrow transplant. The cord blood is removed from the umbilical cord and the placenta soon after a baby is born. Technicians or Physicians collect 3-5 ounces of blood from the cord and placenta which contains about a teaspoon of stem cells.

Potential advantages of cord blood:
  • The cells are somewhat more versatile than bone marrow cells, meaning that cord blood transplants have the potential to successfully treat a wider range of blood diseases.
  • The HLA profile of cord blood, meaning how similar it is to the recipient's own cells, does not need to match the recipient as closely as does bone marrow. There is less chance of rejection of the transplant.
  • There is a ready supply of cord blood, and collection of it does no harm to mother or baby.

Disadvantages of cord blood:

  • Finite source of cord blood stem cells. This means there often aren't enough cells in one collection to treat an adult.
  • Once a cord blood is transplanted, there are no more cells readily available from that source.
  • The cord blood stem cells take longer to graft into the patient than do bone marrow transplants.

Another disadvantage of cord blood is that there is no centralized (nationwide) system for collecting and storing of cord blood that is donated. There are, however, private companies that will, for a fee, store a baby's cord blood for their own possible use later in life. Right now only a few hospitals collect donated cord blood and sometimes it is only done for births that happen during particular hours of the day. Also, there is some controversy over what organization should oversee collection and storage of donated cord blood.

Will cord blood ever be more useful?
Researchers at the University of Minnesota and elsewhere are trying to grow cord blood stem cells into other types of cells for new treatments. They are also working to increase transplant success for larger children and adults by multiplying the cells in the lab or by giving transplants from more than one donor.