Has a successful womb transplant actually been done?
No, but a team led by
Mats Brännström of the University of Gothenburg’s Sahlgrenska Hospital in Sweden is preparing to try early next year. He told
New Scientist that his team is reviewing 10 potential patients, and hoping to transplant wombs into maybe five or six who are most suitable.
So why all the fuss now?
One of the potential donors, a British 56-year-old called Eva Ottosson,
told journalists about a proposal to donate her womb to her 25-year-old daughter, Sara, who lives in Stockholm, Sweden. Sara has a condition called Mayer-Rokitansky-Kuster-Hauser syndrome, which means she has no uterus herself, and is also missing parts of her vagina. If Sara is chosen for the procedure and it works, her eggs will be fertilised by her partner’s sperm and implanted in the same womb from which she herself was born.
Has a womb transplant been attempted before?
Yes. In 2000,
Saudi Arabian surgeons implanted a womb into a 26-year-old woman who had had her own uterus removed at age 20 because of serious bleeding following a caesarean section. But they had to remove it 99 days later because of blood clots in associated blood vessels. The donor was a 46-year-old who had been advised to have a hysterectomy because of ovarian cysts. The news came to light in 2002 at a scientific meeting.
How successful has the procedure been in animals?
Brännström’s group has done a series of experiments in progressively larger animals. In 2002, mice with transplanted wombs successfully gave birth to pups, and
a year later Brännström revealed that the pups were healthy and able to breed normally. Brännström told
New Scientist today that since then, he has successfully transplanted wombs into sheep and baboons, always from related donors. In much more recent, unpublished research, however, he demonstrated in rats that it’s possible to transplant wombs from unrelated females.
When it comes to people, what will the procedure involve?
Brännström says he will transplant the womb itself, plus all uterine arteries and veins to supply and drain blood from the organ. No nerves will be transplanted. Then the recipient will receive low doses of immunosuppressive drugs to prevent rejection. He expects the organ will be accepted more easily than most transplants because pregnancy itself is an immunoprivileged condition, in which foreign material from the father is accepted by the body’s immune system. An immediate pregnancy “will probably help the uterus to be accepted”, he says.
What are the major hurdles?
Brännström says that the surgery itself will be the most difficult step. Compared to other, relatively isolated organs, such as the kidneys, the uterus is deeply embedded and hard to get at, and so may be technically difficult to transplant. “But we’ve overcome it in all animal models,” he says.
And the risks?
Rejection is the main worry. And as with all pregnancies, there are risks of hypertension, diabetes and many other complications.
If a woman has no womb at all, or one that’s damaged, wouldn’t it be simpler just to fertilise her eggs and implant them in the womb of a surrogate mother?
“That would be a reasonable alternative,” says Brännström. But in many countries, including Sweden, surrogacy is illegal, he says. Also, there may be extra physical strain and risks for older women, such as Sara’s mother, in carrying babies – although Brännström acknowledges that surgery to remove the organ is also risky for older donors.
Is anyone else attempting this?
Other groups investigating the possibility include one led by
Richard Smith of the Chelsea and Westminster Hospital in London, and
another led by
Giuseppe Del Priore at the New York Downtown Hospital.
