BioEd Online

Womb transplants in humans should be possible within five years, say scientists in Sweden who have successfully transplanted uteruses in sheep. The procedure would allow women who have functioning ovaries but no womb to carry their own children, and the researchers say they have already been contacted by hundreds of women who are interested in having such a transplant.

There are several reasons why a woman can lack a uterus. Some, with a condition called Rokitansky syndrome, are born without a vagina or a uterus. Others can lose their womb, for example through cervical cancer, or if the organ ruptures during childbirth. The only current way such patients can have a child is if another woman carries the baby.

Mats Brannstrom and his colleagues at Sahlgrenska Academy in Gothenburg have worked for several years on transplanting uteruses in mice, and the recipients have successfully given birth. The group has now been able to remove a uterus from a sheep and replace it several hours later, then show after 2-3 months that the organ is functioning normally. They presented their research yesterday at the annual meeting of the European Society of Human Reproduction and Embryology in Prague, the Czech Republic.

The next step is to try to get the sheep pregnant and to give birth. After that, the aim is to transplant uteruses between different animals, to check that immune rejection can be controlled using immunosuppressant drugs. Once that's done, Brannstrom thinks that the procedure should be tried in primates, and only then in humans. Even so, he is hopeful that human womb transplants will be possible in five years.

Relatives to lend a womb

Although wombs could be transplanted from dead donors, Brannstrom says the ideal situation would be for a woman to receive the organ from her older sister or mother, to minimize the problem of immune rejection. Cases in which women in their 60s who have given birth after egg donation suggest that womb function does not deteriorate significantly with age. The recipient would have eggs harvested for in vitro fertilization (IVF) before the transplant; the eggs would then be fertilized and the embryos frozen, to be implanted after the womb transplant. After having children, the womb would be removed, so the patient would not need to take immunosuppressant drugs for life.

One human uterus transplant was carried out in 2000 in Saudi Arabia. A 26-year-old woman who had lost her uterus six years before after massive bleeding following a caesarian section, received a uterus from a 46-year-old woman who was having a hysterectomy because of ovarian disease¹. The researchers who performed the transplant claim that the organ was initially healthy, but after 99 days the recipient developed a life-threatening blood clot and it had to be removed.

Brannstrom says he doesn't think that any further human transplants should be carried out until the animal work is complete. "It's not a life-saving operation; it's about improving quality of life," he says. "So we have to be sure it's a safe procedure."

Although Brannstrom acknowledges that there may be concerns (some might find it unpalatable that a woman could carry her baby in the same womb that her mother used to carry her, for example) he doesn't think that it raises significant ethical issues compared with procedures such as egg or sperm donation. "It's not transmission of genetic material," he says. "It's just lending your uterus out."

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