Uterus transplants fail again: Why are they so difficult?

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Out of four uterus transplants that were recently performed at a U.S. hospital, three were not successful, doctors announced today. What makes uterus transplants so challenging, and why might they fail?

In mid-September, doctors at Baylor University Medical Center in Dallas performed four uterus transplants on women who were born without the organ, according to a statement from the university Wednesday. The uteruses came from living donors, marking the first time such transplants have been performed in the United States. In February, doctors at the Cleveland Clinic performed the country's first uterus transplant, but the organ came from a deceased donor.

However, three of the women who received the transplants at Baylor needed to have their uteruses removed after follow-up tests showed that in all three cases, the organ was not receiving proper blood flow, the statement said. The patient at the Cleveland Clinic who received the first transplanted uterus also needed to have the organ removed, because of a yeast infection that had developed and caused complications.

So far, there have been 16 uterus transplants in the world that have been reported, and eight were not successful.

The main challenge for uterus transplants is that the surgery is very new, so it will take time to perfect.

"It's not so much more difficult [than other transplants]; it's just that it's a brand-new surgery, so the learning curve is steep figuring out how to actually do it," Dr. Alexander Maskin, an assistant professor of surgery at the University of Nebraska Medical Center (UNMC), told Live Science in an interview in March. Maskin was not involved with the Baylor or Cleveland Clinic cases, but he is helping plan a uterus transplant program at UNMC.

Three decades ago, kidney transplants took 6 to 10 hours to complete, but can now be done in an hour and a half, Maskin said.

Indeed, doctors at both Baylor and Cleveland Clinic said that the unsuccessful surgeries will likely result in changes to the surgery protocols, in the hope of improving future outcomes.

The doctors at Baylor "believe the valuable learnings from the cases will result in recommendations to change the current protocols in operative and post-operative management of uterine transplant patients, with specific attention to the thickness of the uterine veins," the medical center's statement said.

Another challenge is that uterus transplants are slightly more complex than other organ transplants. "The uterus lies deep inside the pelvis and [so] it's difficult to access," Dr. Andreas Tzakis, who led the Cleveland Clinic uterus transplant surgery, said at a news conference in March. "And the [blood] vessels are all deep inside the pelvis as well. So it's a little bit more difficult," than other transplants, Tzakis said.

Uterus transplants can fail for the same general reasons that any organ transplant fails, Maskin said.

The main reasons for failure include organ rejection, which is when the patient's immune system attacks the organ; an infection of the organ (as happened in the Cleveland case); or problems with the organ's blood supply (as happened in the Baylor cases).

In 2014, doctors in Sweden performed nine uterus transplants using organs from living donors. In two of those cases, the transplanted organs had to be removed after the surgery. But five of the Swedish women were able to become pregnant and give birth.

Members of that Swedish team assisted in the Baylor surgeries. One patient from Baylor still has her transplanted uterus, and there are currently no signs of rejection, the statement said.

"We are cautiously optimistic that she could ultimately become the first uterine transplant recipient in the U.S. to make it to the milestone of uterine functionality," the statement said.

The plan is for that patient to undergo in vitro fertilization (IVF) in six to 12 months, according to Time. Baylor is planning a total of 10 uterus transplants before the end of the year, but doctors will assess the results from the first four surgeries before continuing with the other six, Time said.

Original article on Live Science.

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