The field of uterus transplants has evolved rapidly.Adobe

The first modern attempt at transferring a uterus from one human to another occurred at the turn of the millennium. But surgeons had to remove the organ, which had become necrotic, 99 days later. The first successful transplant was performed in 2011 — but even then, the recipient wasn’t immediately able to get pregnant and deliver a baby. It took three more years for the first person in the world with a transplanted uterus to give birth. 

More than 70 such babies have been born globally in the decade since. “It’s a complete new world,” said Giuliano Testa, chief of abdominal transplant at Baylor University Medical Center.

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Almost a third of those babies — 22 and counting — have been born in Dallas at Baylor. On Thursday, Testa and his team published a major cohort study in JAMA analyzing the results from the program’s first 20 patients. All women were of reproductive age and had no uterus (most having been born without one), but had at least one functioning ovary. Most of the uteri came from living donors, but two came from deceased donors.

Fourteen women had successful transplants, all of whom were able to have at least one baby.  

“That success rate is extraordinary, and I want that to get out there,” said Liza Johannesson, the medical director of uterus transplants at Baylor, who works with Testa and co-authored the study. “We want this to be an option for all women out there that need it.”

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Six patients had transplant failures, all within two weeks of the procedure. Part of the problem may have been a learning curve: The study initially included only 10 patients, and five of the six with failed transplants were in that first group. These were “technical” failures, Testa said, involving aspects of the surgery such as how surgeons connected the organ’s blood vessels, what material was used for sutures, and selecting a uterus that would work well in a transplant. 

The team saw only one transplant fail in the second group of 10 people, the researchers said. All 20 transplants took place between September 2016 and August 2019.

Only one other cohort study has previously been published on uterus transplants, in 2022. A Swedish team, which included Johannesson before she moved to Baylor, performed seven successful transplants out of nine attempts. Six women, including the first transplant recipient to ever deliver a baby back in 2014, gave birth.

“It’s hard to extract data from that, because they were the first ones that did it,” Johannesson said. “This is the first time we can actually see the safety and efficacy of this procedure properly.”

So far, the signs are good: High success rates for transplants and live births, safe and healthy children so far, and early signs that immunosuppressants — typically given to transplant recipients so their bodies don’t reject the new organ — may not cause long-term harm, the researchers said. (The uterine transplants are removed after recipients no longer need them to deliver children.) And the Baylor team has figured out how to identify the right uterus for transfer: It should be from a donor who has had a baby before, is premenopausal, and, of course, who matches the blood type of the recipient, Testa said.

People who donated a uterus did have some complications, but they were similar to other gynecological hysterectomies, and no one had long-term complications, the researchers noted. Over the course of the study, the team changed how they extract the uterus from a traditional midline incision to a minimally invasive technique.

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“They’ve really embraced the idea of practicing improvement as you go along, to understand how to make this safer or more effective. And that’s reflected in the results,” said Jessica Walter, an assistant professor of reproductive endocrinology and infertility at Northwestern University Feinberg School of Medicine, who co-authored an editorial on the research in JAMA

But while the field has made progress, some people question the idea of transplanting uteri. “Even in medicine, there’s a tremendous amount of skepticism,” said Walter. 

Absolute uterine-factor infertility — when a woman doesn’t have a uterus, either because she was born without one or had to have it removed — affects about one in 500 women worldwide.

Bioethicists have raised concerns about uterus transplants in the past, saying that there are other options, such as surrogacy and adoption, that could pose less risk to the patient and fetus. But Walter and Johannesson both separately said that infertility is a disease, and people deserve treatment. 

Walters was a skeptic herself when she first learned about uterine transplants. The procedure seemed invasive and complicated. But she did her fellowship training at Penn Medicine, home to one of just four programs in the U.S. doing uterine transplants. 

“The firsts — the first time the patient received a transplant, the first time she got her period after the transplant, the positive pregnancy test,” Walter said. “Immersing myself in the science, the patients, the practitioners, and researchers — it really changed my opinion that this is science, and this is an innovation like anything else.” 

The field has evolved rapidly, but there are challenges to come that go beyond the science. Like in-vitro fertilization and surrogacy, the two main treatments for infertility, a uterus transplant is expensive. 

Many transgender women are hopeful that uterine transplants might someday be available for them, but it’s likely a far-off possibility. Scientists need to rewind and do animal studies on how a uterus might fare in a different “hormonal milieu” before doing any clinical trials of the procedure with trans people, Wagner said.

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Among cisgender women, more long-term research is still needed on the donors, recipients, and the children they have, experts said.

“We want other centers to start up,”Johannesson said. “Our main goal is to publish all of our data, as much as we can.”