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 levels and pH would aid in diagnosis of a condition, such as anemia, or delivery plan, if termination of the pregnancy is being considered or special plans must be made. Umbilical cord blood gas analysis may assist with clinical management and excludes the diagnosis of birth asphyxia in approximately 80% of depressed newborns at term. Severe fetal growth issues in conjunction with low oxygen in the fetus’ blood and high levels in the mother’s blood also indicate the use of PUBS. With more detailed observations and information on fetal tissue perfusion and metabolism, better predictions on development can be made.