British doctors have carried out the inaugural womb transplant in the U.K., with the organ being donated by the recipient's sister.
The 34-year-old married woman received the womb – also called the uterus – during an operation lasting nine hours and 20 minutes at the Churchill Hospital in Oxford, which is part of Oxford University Hospitals NHS Foundation Trust.
Her sister, 40, has completed her own family by giving birth to two children and was willing to donate her womb.
The recipient, who lives in England and does not wish to be named, has stored embryos with the aim of undergoing IVF later this year.
The lead surgeons for the transplant were Professor Richard Smith, clinical lead at the charity Womb Transplant U.K. and consultant gynecological surgeon at Imperial College Healthcare NHS Trust, and Isabel Quiroga, consultant surgeon at the Oxford Transplant Centre, part of Oxford University Hospitals.
Speaking to the Deutsche Presse-Agentur (dpa), professor Smith said the experience had been "quite remarkable," adding that the operation had been a "massive success."
"It was incredible. I think it was probably the most stressful week in my surgical career but also unbelievably positive. The donor and recipient are over the moon, just over the moon," he added.
"I'm just really happy that we've got a donor who is completely back to normal after her big op and the recipient is, after her big op, doing really well on her immunosuppressive therapy and looking forward to hopefully having a baby."
Miss Quiroga said she was "thrilled," adding that, following the operation, transplant staff was still cautiously taking it all in.
"It was a very proud moment but still quite reserved – the first two weeks after the operation are nerve-racking," she said.
"Now, I feel extremely proud of what we've achieved and desperately happy for her."
Miss Quiroga said the patient was "incredibly happy," adding: "She was absolutely over the moon, very happy, and is hoping that she can go on to have not one but two babies.
"Her womb is functioning perfectly and we are monitoring her progress very closely."
The woman receiving the womb was born with Mayer-Rokitansky-Kuster-Hauser (MRKH), a rare condition that affects around one in every 5,000 women.
In MRKH, women have an underdeveloped or missing womb. The first sign of the condition is when a teenage girl does not have periods.
However, their ovaries are intact and still function to produce eggs and female hormones, making conceiving via fertility treatment a possibility.
Before receiving her new womb, the woman had two rounds of fertility stimulation to produce eggs.
Eight embryos have reached the blastocyst stage – which means they have a good chance of success in IVF – and were frozen for when the patient undergoes treatment at the Lister Fertility Clinic in central London later this year.
Prof Smith said that, at present, the transplanted womb is "functioning exactly as it should" and the plans for IVF are on track.
The woman will need to take immunosuppressant drugs throughout any future pregnancy to prevent her body from rejecting the donor organ.
The transplant is expected to last for a maximum of five years before the womb is removed.
