For the fourth patient, tests indicate good blood flow to the uterus with no signs of rejection or infection. "We are cautiously optimistic that she could ultimately become the first uterine transplant recipient in the US to make it to the milestone of uterine functionality," a statement from Baylor University Medical Center explained.

16 uterine transplants have been performed around the world thus far. In fact, the Swedish team that assisted doctors at Baylor are considered experts on the procedure. There have been five births following procedures they've completed. Following these most recent transplants, both surgical teams say they've gained valuable knowledge from the three unsuccessful cases that will prove beneficial to future operations. Changes will include updates to protocols and post-op management with special attention to the thickness of the uterine veins.

Back in February, the Cleveland Clinic performed the first uterus transplant in the US. In that case, the 26-year-old recipient would have needed to have the organ removed after one or two pregnancies due to medications that kept her body from rejecting it. Due to compromised blood flow caused by an infection in the weeks that followed, the transplanted uterus was removed in March.