Other experts said if the operations are successful, womb transplants could be an alternative for women who have few choices.

"What remains to be seen is whether this is a viable option or if this is going to be confined to research and limited experimentation," said Dr. Yacoub Khalaf, director of the Assisted Conception unit at Guy's and St. Thomas' hospital in London, who was unconnected to any of the womb transplant projects.

Brannstrom warned the transplants might not result in children but remained optimistic.

"This is a research study," he said. "It could lead to (the women) having children, but there are no guarantees ... what is certain is that they are making a contribution to science."