More than 2,000 frozen eggs and embryos stored at a Cleveland-area fertility clinic may no longer be viable after temperatures in a storage bank rose over the weekend.

A liquid nitrogen storage tank at University Hospitals Ahuja Medical Center unexpectedly heated up sometime between Saturday afternoon and Sunday morning, hospital administrators told the Cleveland Plain Dealer. While the extent of the loss is still unclear, the hospital informed about 700 patients that their frozen eggs and embryos may have suffered damage. Some of the samples were frozen in the 1980s.

University Hospitals does not know how or why the temperature fluctuated and has launched an investigation to determine what happened, it said in a statement Thursday. It is unknown whether the problem was caused by a human error or mechanical failure.

The potential damage to hundreds or thousands of eggs would be a devastating financial and emotional blow to the respective patients, which include women donating their eggs, women hoping to delay a pregnancy or women storing extra embryos while they undergo in vitro fertilization.

The process of removing and freezing a woman’s eggs is arduous and can cost upward of $10,000, plus hundreds of dollars in yearly storage fees. And for some families, the treatment is their only chance at conceiving a child.

The only way to find out if the samples are still viable is to thaw and implant them, the hospital told the Cleveland Plain Dealer. Some specimens that already were thawed since Sunday for planned procedures were found not to be viable, the Plain Dealer reported.

Patricia DePompei, president of University Hospitals Rainbow Babies & Children’s Hospital, and James Liu, Department of Obstetrics and Gynecology, UH Cleveland Medical Center

“We are so very sorry this happened and we want to do all that we can to support our patients and families through this very difficult time,” Patti DePompei, president of University Hospitals Rainbow Babies & Children’s Hospital and MacDonald Women’s Hospital, said in a video posted on Facebook Thursday.

DePompei said hospital staff members have consulted with numerous experts to “better understand the cause of this temperature fluctuation and ensure that it doesn’t happen again.”

“It’s devastating,” DePompei told WKYC. “It’s absolutely devastating.”

The storage facility was not staffed overnight Saturday. When embryologists arrived at the center Sunday morning, an alarm alerted them to a temperature change in the tank, administrators told the Plain Dealer.

The temperature had increased in the top of the tank but had stayed at the proper levels at the bottom of the tank, James Liu, chairman of the Department of Obstetrics and Gynecology at UH Cleveland Medical Center, told WKYC.

“We are currently looking at what specimens existed in that gradient,” Liu told WKYC. “Our fear is a significant number of embryos and eggs have been compromised.”

Each vial contained two to three eggs or embryos from each patient. All of the samples have been moved to another tank, which is being monitored at all hours and maintained at the correct temperature. None of the eggs or embryos will be destroyed, WKYC reported, and University Hospitals has reported the incident to federal regulators.

The hospital may waive the cost of future procedures and treatments for the patients affected, according to WKYC. The hospital set up a call center to arrange meetings or calls between patients and their physicians to address their concerns.

“Some of the eggs and embryos that were stored date back decades,” DePompei told WKYC. “People move, their addresses change, but we’ve made our best attempts to track down everyone.”

No malfunction of this kind has been reported at any other fertility clinic in the country, a spokesman for the American Society for Reproductive Medicine told NBC News.

“Our hearts go out to the patients who have suffered this loss,” Sean Tipton, chief policy officer at ASRM, told NBC News.

The number of women who freeze their eggs has skyrocketed in the past several years. The Society for Assisted Reproductive Technology, which represents the majority of fertility clinics in the United States, found in its latest survey that the number of women freezing their eggs has gone from 475 in 2009 to nearly 8,000 in 2015.

Egg freezing has provided thousands of women with the choice to start a family at a later time. But the procedure is a gamble, and outcomes are hard to predict.

Up to 15 percent of eggs typically don’t survive the thawing process. On average, a woman freezing 10 eggs at age 36 has a 30 to 60 percent chance of having a baby with them, according to published studies. The odds are better for younger women, but the chance of success varies significantly from person to person.

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