Umbilical cord is used in place of a bone marrow transplant in the treatment of blood disorders such as leukemia, with donations released for transplant through one registry, Netcord.org, passing 1,000,000 as of January 2013. Cord blood is used when the patient cannot find a matching bone marrow donor; this "extension" of the donor pool has driven the expansion of public banks. The umbilical cord in some mammals, including cows and sheep, contains two distinct umbilical veins. There is only one umbilical vein in the human umbilical cord. In some animals, the mother will gnaw through the cord, thus separating the placenta
Percutaneous umbilical cord blood sampling issues, and infections. In 1958, James L.S. recognised that umbilical cord blood gas analysis can give an indication of preceding fetal hypoxic stress. It has since become widely accepted that umbilical cord blood gas analysis can provide important information about the past, present and possibly the future condition of the infant. PUBS dates back to 1964 when Freda and Adamsons reported the removal of a uterus containing a fetus who had a buildup of fluid and ended up dying; however, this was one of the first procedures that showed promise for current day PUBS. Valenti hypothesized in 1972 that the