STOCKHOLM — Nine women in Sweden have successfully received transplanted wombs donated from relatives in an experimental procedure that has raised some ethical concerns. The women will soon try to become pregnant with their new wombs, the doctor in charge of the pioneering project has revealed.

The women were born without a uterus or had it removed because of cervical cancer. Most are in their 30s and are part of the first major experiment to test whether it’s possible to transplant wombs into women so they can give birth to their own children.

In many European countries, including Sweden, using a surrogate to carry a pregnancy isn’t allowed.

Life-saving transplants of organs such as hearts, livers and kidneys have been done for decades, and doctors are increasingly transplanting hands, faces and other body parts to improve patients’ quality of life. Womb transplants – the first ones intended to be temporary, just to allow childbearing – push that frontier even farther and raise some new concerns, such as whether it’s ethical to use live donors for an experimental procedure that doesn’t save lives.

There have been two previous attempts to transplant a womb – in Turkey and Saudi Arabia – but both failed to produce babies.

“This is a new kind of surgery,” Dr. Mats Brannstrom told The Associated Press in an interview from Goteborg. “We have no textbook to look at.”

Brannstrom said the nine womb recipients are doing well. Many already had their periods six weeks after the transplants, an early sign that the wombs are healthy and functioning.

The transplant operations did not connect the women’s uteruses to their fallopian tubes, so they are unable to get pregnant naturally. But all who received a womb have their own ovaries and can make eggs. Before the operation, they had some removed to create embryos through in-vitro fertilization. The embryos were then frozen and doctors plan to transfer them into the new wombs, allowing the women to carry their own biological children.