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.