Successful uterine transplantation in the mouse: pregnancy and post-natal development of offspring.

BACKGROUND Uterine transplantation could serve as a tool in studies of the physiology of implantation/pregnancy, and is also a possible future treatment for patients with absolute uterine infertility. Here, the first live-born offspring in any uterine transplantation model is reported. METHODS A syngeneic mouse model with a uterus transplanted, by end-to-side aorta/vena cava vascular anastomoses, alongside the native uterus was used. The cervix was attached to a cutaneous stoma. Pregnancy rate and offspring (birth weight, growth and fertility) was evaluated after blastocyst transfer to the native and the grafted uterus of transplanted mice and to controls. RESULTS Pregnancy rates were comparable in the grafted uterus (8/12 animals became pregnant) and the native uterus (9/12 pregnant) of transplanted animals and controls (8/13 pregnant). In a separate set of animals, the native uterus was removed at transplantation to exclude influences from the native uterus on the pregnancy potential of the graft; two of four animals became pregnant after blastocyst transfer. The weights/lengths of fetuses (gestational day 18) and gestational lengths were similar in all groups. Offspring were delivered and the growth trajectories (up to 8 weeks) of offspring delivered from grafted or native uteri of transplanted mice were similar as compared with controls, and all were fertile. The second-generation offspring from transplanted animals were all fertile with normal birth weights. CONCLUSIONS These observations document the capacity of a transplanted uterus to harbour pregnancies to term, and reveal that offspring from a transplanted uterus develop to normal fertile adults.