Just under a year ago, a Brazilian woman delivered a healthy, 5.6-pound baby girl via caesarean section. Given the fact that this newborn was one of roughly 350,000 babies born on December 15, 2017, her entry into the world may seem unremarkable. (Besides the whole miracle of life part.) But as a team of Brazilian scientists reports in The Lancet, the infant is unique in more ways than one: Not only does she rank amongst around a dozen children born via transplanted wombs, but she’s also the first baby born via a womb transplanted from a deceased donor.

The transplant recipient, who was born without a uterus, has a rare genetic condition called Mayer-Rokitansky-Küster-Hauser syndrome, Susan Scutti writes for CNN. Affecting one in 4,500 women, MRKH renders the vagina and uterus underdeveloped or absent. External genitalia retains a normal appearance, and ovaries continue to produce eggs—meaning the patient was able to undergo in-vitro fertilization prior to the procedure.

The donor, a 45-year-old woman who died of a blood vessel burst in the brain, was deemed a promising match because she’d successfully given birth three times. Karen Weintraub of Scientific American notes that the deceased also donated her heart, liver and kidneys.

According to The Guardian’s Nicola Davis, the transplant took place in September 2016. Over the course of a painstaking 10-and-a-half-hour operation, surgeons connected the 32-year-old recipient’s veins, arteries, ligaments and vaginal canals to the donor’s uterus. Following the procedure, the team gave the soon-to-be mother medicine that weakened her immune system, making the body less likely to reject the unknown womb.

37 days after the procedure, the woman started her first menstrual cycle. At the five-month post-transplant mark, her body showed no signs of rejecting the uterus, and at the seven-month mark, doctors were confident enough to begin the implantation process. The team transferred a fertilized embryo provided by the patient prior to the transplant into the womb, and 10 days later, the pregnancy was confirmed.

Doctors delivered the baby via C-section at the Hospital das Clinicas, University of São Paulo School of Medicine, during the 35th week of the pregnancy. (According to CNN’s Scutti, this early timeframe stemmed from concerns that delivery beyond 34 to 36 weeks would entail the risk of restricted fetal growth caused by ongoing immunosuppressive therapy.) The mother’s transplanted uterus was removed during the procedure in order to enable her to stop taking expensive immunosuppressive drugs.

At the time of the study’s writing, the seven-month, 20-day-old baby girl weighed nearly 16 pounds. Both mother and daughter appeared to be the picture of health.

Since 2013, at least 11 babies have been conceived via uterine transplants from living donors. But as Emily Baumgaertner reports for The New York Times, the Brazilian case study represents the first live birth via a transplant from a deceased donor. 10 previous attempts carried out in the United States, Turkey and Czech Republic proved unsuccessful.

Allan D. Kirk, chief surgeon at Duke University Health System, was not involved in the research. Still, he tells Baumgaertner, “We talk about life-saving transplants. This is a life-giving transplant, a new category.”

Today, most women experiencing fertility issues look to adoption or surrogacy. Womb transplants—either from living donors, who are often recipients’ relatives, or deceased donors—offer another option, albeit one that remains at highly experimental stages.

There are pros and cons to both transplant styles, Kate O’Neill, a co-lead investigator of the University of Pennsylvania’s uterus transplant program who was not involved in the research, tells Scientific American. With living donors, surgeons have ample time to assess the organ’s viability. With deceased donors, the process is more rushed, as surgeons have to transfer the womb before it becomes unusable. At the same time, O’Neill says, surgeons can extract more vaginal and blood vessel tissue than would be possible with a living donor. Other advantages of using deceased donors include a wider donor population and the avoidance of surgical risks posed to live donors.

Moving forward, lead author Dani Ejzenberg, a gynecologist at the University of São Paulo, plans on repeating the procedure in two more patients.

“We are focused on improving our protocol to be able to repeat this success story,” Ejzenberg explains to Newsweek’s Kashmira Gander.

And the Brazilian team isn't the only one investigating uterine transplants: Three U.S. groups, including O’Neill’s, are currently working toward successful transplantations from deceased donors, and a British team led by Richard Smith of Womb Transplant U.K. is pursuing transplants involving both living and deceased donors.