Nine women in Sweden have received new wombs since 2012, but two had to have them removed because of complications, Fox News reports.

The women received wombs donated by their mothers or other close relatives in an experimental procedure designed to test whether it's possible to transfer a uterus so a woman can give birth to her own biological child. The women had in vitro fertilization before the transplants, using their own eggs.

"We have already begun transferring embryos into four of the women and plan to make attempts with the others when they are ready," said Dr. Mats Brannstrom, a professor of obstetrics and gynecology at the University of Goteburg, who is leading the research.

Brannstrom predicted that three or four of the seven women might successfully give birth.

There have been two previous attempts to transplant a womb - in Turkey and Saudi Arabia - but both failed to produce babies. Doctors in Britain and Hungary also are planning similar operations, but using wombs from women who had just died.

The transplants are intended to benefit women unable to have children because they lost a uterus to cancer or were born without one.

Brannstrom said the transplanted wombs would be removed after a maximum of two pregnancies.