Two Swedish women have been given the wombs of their mothers in the world's first mother-to-daughter uterus transplants.
Specialists at the University of Goteborg completed the surgery over the weekend without complications, but say they will consider the procedures successful unless the women become pregnant after their observation period ends a year from now.
"We are not going to call it a complete success until this results in children," Michael Olausson, one of the Swedish surgeons said."That's the best proof."
He said the daughters started in-vitro fertilisation, or IVF, before the surgery.
IVF uses hormones to stimulate the ovaries, which the women already had, to produce eggs. Scientists would fertilise the eggs with sperm in a lab, before freezing the embryos. The frozen embryos would then be thawed and transferred if the women are in good health after the observation period, Dr Olausson said. After a maximum of two pregnancies, the wombs will be removed again.
The university said one recipient had her uterus removed many years ago due to cervical cancer and the other was born without a uterus. Both women are in their 30s.
"Both patients that received new uteri are doing fine but are tired after surgery. The donating mothers are up and walking and will be discharged from the hospital within a few days," team leader Mats Brannstrom said.
Turkish doctors last year said they performed the first successful uterus transplant, giving a womb from a deceased donor to a young woman. Dr Olausson said that woman was doing fine, but he was not sure whether she had started undergoing fertility treatment yet.
In 2000, doctors in Saudi Arabia transplanted a uterus from a live donor, but it had to be removed three months later because of a blood clot.