LONDON — In a medical first, a woman in Sweden has given birth after receiving a womb transplant, the doctor who performed the pioneering procedure said Friday.

The 36-year-old mother received a uterus from a close family friend last year. Her baby boy was born prematurely but healthy last month, and mother and child are now at home and doing well. The identities of the woman and her husband were not disclosed.

“The baby is fantastic,” said Dr. Mats Brannstrom, a professor of obstetrics and gynecology at the University of Gothenburg and Stockholm IVF who led the research and delivered the baby with the help of his wife, a midwife. “But it is even better to see the joy in the parents and how happy he made them.”

Brannstrom said it was “still sinking in that we have actually done it.”

The feat opens up a new but still experimental alternative for some of the thousands of women each year who are unable to have children because they lost a uterus to cancer or were born without one. Before this case proved the concept can work, some experts had questioned whether a transplanted womb would be able to nourish a fetus.

Others have questioned whether such an extreme step – expensive and fraught with medical risks – would even be a realistic option for many women.

Dr. Glenn Schattman, past president of Society for Assisted Reproductive Technologies and a Cornell University fertility specialist, said womb transplants are likely to remain very uncommon.

“This would not be done unless there were no other options,” he said. “It requires a very long surgery and not without risk and complications.”

For the proud parents, the years of research and experimentation were well worth the wait.

“It was a pretty tough journey over the years, but we now have the most amazing baby,” the father said in a telephone interview. “He is very, very cute, and he doesn’t even scream, he just murmurs.”

He said he and his wife, both competitive athletes, were convinced the procedure would work, despite its experimental nature.

There had been two previous attempts to transplant a womb – in Saudi Arabia and Turkey – but no live births resulted.