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
Uterus transplantation ovum and her husband's sperm, which was then implanted into the transplanted uterus. The uterus may have been damaged in the course of the caesarian delivery and it may or may not be suitable for future pregnancies. A regimen of triple immuno-suppression was used with tacrolimus, azathioprine, and corticosteroids. Three mild rejection episodes occurred, one during the pregnancy, but were all successfully suppressed with medication. Some other women were also reported to be pregnant at that time using transplanted uteri. The unnamed mother, who received a donated womb from a friend, said that she hoped the treatment would be refined