A Texas couple hoped to make history by delivering the first baby in the United States using a donor uterus. The procedure was part of an experimental program at the Cleveland Clinic. But a common fungal infection caused the surgery to fail unexpectedly only a few hours after Lindsey McFarland was introduced as the patient.

Blake, left, and Lindsey McFarland after the transplant surgery. "It's been really encouraging to see all the support from our family and from the doctors and nurses," Blake McFarland told NBC News. "The best experience about it is how much God has looked out for us." Courtesy of Blake McFarland

In their first television interview since the transplant surgery, the couple — Lindsey, 26, and her husband Blake McFarland — spoke of the "emotional roller coaster" of the long, complicated process, their heartbreaking disappointment after losing the organ, and what's next for their family.

"There are days when I'm happy, and then there's days where I'm kind of mad, and then days where I'm sad," Lindsey McFarland told NBC News. "Everyone has said that that's normal."

Lindsey McFarland was still sedated when doctors told her husband they had no choice but to remove the organ.

"You lose more than just the uterus. You lose a lot of the hopes and dreams that you had for the future," Blake McFarland said.

On April 8, Cleveland Clinic doctors identified why the transplant failed, just two weeks after the historic surgery. It was a Candida infection, a common microbe that affects millions of women, which "compromised the blood supply to the uterus, causing the need for its removal," the clinic said in a statement.

Related: Yeast infection ruins first U.S. uterus transplant

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Sudden complications

Lindsey McFarland was born without a uterus, but she always hoped to experience childbirth. The couple are already parents — they have three adopted boys. But the clinical trial in Cleveland seemed like an answer to her dreams of getting pregnant.

As part of the program, she had already undergone in vitro fertilization (IVF) treatment. After a year of being monitored with the donor uterus inside her, doctors would implant the couple's embryos.

Everyone took such good care of me and I'm so thankful for that," said Lindsey McFarland. Stephanie Siegel

In early March, hours after the transplant was announced at a press conference, McFarland noticed bleeding from her incision and was taken to surgery to repair it. During the procedure, doctors discovered the fungal infection had stopped blood flow to the uterus and caused life-threatening complications involving her artery.

"So they had to remove it to protect my health," McFarland told NBC News.

When she awoke, her husband Blake was with her in the intensive care unit. It was a major setback for the program and an emotional shock for the McFarlands.

"It's going to be a while before I work through everything just because I had such high hopes," Lindsey McFarland said.

A week after the removal, another complication with her artery caused loss of blood flow to her leg — and more surgery. Because of the second complication, Lindsey is not eligible for another transplant. The trial, which involves nine more women, will continue once doctors have studied her case.

"We would not proceed with another transplant until we have come up with a clear understanding of how this infection occurred and a clear solution to avoid it from happening [again]," OB-GYN surgeon Dr. Tammaso Falcone, chairman of the Cleveland Clinic Transplant Center, told NBC News.

No regrets

As the McFarlands plan to return to their family in Texas, they have a new dream: Lindsey McFarland's mother has offered to be a surrogate, using their embyros from the IVF.

"We're going to take a few years to focus on our boys and me build up strength and get back to normal," McFarland said. "Then we'll start the process. So we're excited."

"I've always known, from the time I was four years old, that I wanted to adopt," says Lindsey. Their three adopted son "are the perfect fit for our family." Courtesy of Blake McFarland

The McFarlands have no regrets. They are grateful for her recovery and looking forward to seeing their sons again.

"We had the mindset at the beginning that, even if something happens and we lose the uterus, or it just doesn't work out, then we can always say that we gave it a shot and that even if they just learn something from her procedure, that it was a success," Blake McFarland said.

Lindsey McFarland is hopeful for the other women still in the program who may benefit.

"Infertility ... is a journey most people don't understand unless they've dealt with it," she said. "So I think it's amazing that science has come so far to provide families and couples with an opportunity like this to build their family."