A medical first was achieved in Texas– and in America– after a woman just gave birth using a transplanted uterus. You read that right. For the first time in American history, a woman who was born without a uterus, got pregnant, carried to term and gave birth to a baby.

This was possible because of a uterus transplant clinical trial at Baylor University Medical Center in Dallas, Texas. The new mother, who asked for her identity to remain private, was among other participants diagnosed with “absolute uterine factor infertility” (AUI) and/or Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome. Meaning, they do not have a uterus or their uterus is not functional.

How did this happen?

Baylor is the only program to use uteruses from both living and deceased donors. In this particular case, the donor, Taylor Siler, 36, is a registered nurse in the Dallas area who donated her uterus. Siler, an “altruistic” living donor, is one of 70 so far that have expressed interest Baylor’s clinical trial.

A mother of two children already, Siler chose to offer someone else the chance of giving birth. After watching a local news program about the clinical trial, she and her husband considered her participation.

Potential donors are between the ages of 30-60 and undergo extensive screening of their physical and mental health before approval. Once approved, donors are operated on and experience a 12-week recovery period.

Recipients and trial participants are between 20-25 years-old. Once recipients receive the transplanted uterus, they undergo recovery and hope to menstruate within four months of the surgery. Successful transplants lead to in vitro fertilization (IVF). (IVF is necessary because the participants’ functioning ovaries are not attached to the transplanted uterus.)

According to Baylor, it takes five hours to remove the womb from the donor and five hours to transplant it into the recipient. Donors and recipients remain anonymous, however, in this case, Siler and the recipient exchanged letters on the day of the surgery and Siler was informed when the recipient was pregnant and gave birth.

Baylor’s first trial includes ten transplants; eight of which have already been performed. Three transplants failed; one recipient is pregnant.

The first successful uterus transplant in the world occurred in Sweden. The Gothenburg Sahlgrenska University medical team pioneered the first uterus transplant trial, resulting in eight births. Dr. Johannesson, of the team members who moved to Dallas to assist in Baylor’s program, told TIME: “We were very proud of the first birth in Sweden. But this birth is what’s going to make the field grow, because this is the first time this has been replicated anywhere else. This step is equally, if not even more, important.”