Just two weeks after receiving the first uterus transplant in the United States, a patient at the Cleveland Clinic suddenly developed a serious complication last month, and on March 8 the transplant had to be removed. No details were given.

On Friday, the clinic explained what went wrong: a common yeast infection.

In a written statement, the clinic said, “Preliminary results suggest that the complication was because of an infection caused by an organism that is commonly found in a woman’s reproductive system. The infection appears to have compromised the blood supply to the uterus, causing the need for its removal.”

The infection was caused by a fungus, a type of yeast called Candida albicans, two of the doctors who performed the surgery said in an interview. It is normally found in the vagina, living in balance with bacteria and other microbes. But illness or some medications can disrupt the balance, allowing for a problematic overgrowth of the yeasts.

The surgeons said that since yeasts normally inhabit the genital tract, they could have come from either the donor or the recipient. The transplant included some vaginal tissue from the donor, as well as the uterus.