Pregnancy after syngeneic uterus transplantation and spontaneous mating in the rat.

Background: Uterus transplantation (UTx) research aims towards the introduction of UTx as a treatment for uterine factor infertility. The rat model is the principal rodent model used and this study aims to assess the potential for pregnancy and to assess effects on pregnancy outcome.

Methods: Female Lewis rats underwent hysterectomy and received syngeneic uterine transplants (with one horn removed) by end-to-side anastomosis between the common iliac vessels of the recipient and the graft. The graft was placed in an orthotopic position with anastomosis to the upper part of the native uterine horn and vagina to allow for pregnancy by mating. Controls had only one uterine horn removed. Mating and pregnancy frequencies, successful deliveries and pup weight trajectory were compared.

Results: Pregnancy was achieved in rats after UTx with the pregnancy rate, number of pups and growth trajectory of pups being similar to controls. However, numbers of resorbed pregnancies and arrested parturitions were more common in the UTx group.

Conclusions: A model for orthotopic UTx was developed and pregnancies with live offspring were for the first time demonstrated in the rat model of UTx. The model will be useful in future studies of fertility after UTx.