The Edinburgh Zoo confirmed Monday that the United Kingdom’s only female giant panda, Tian Tian, is no longer pregnant. The zoo said there's no evidence that she had a miscarriage and that late reabsorption of the fetus could have taken place.

“Tian Tian’s hormone levels have now returned to normal, so we can confirm that she is no longer pregnant,” Iain Valentine, director of giant pandas for the Royal Zoological Society of Scotland, said in a statement. “Panda reproduction and biology is complex; all data gathered since conception took place pointed to a pregnant panda likely to carry to full term, sadly this did not happen.”

The zoo said Tian Tian is in great health and being closely monitored by experts. She was artificially inseminated on April 13 after she and her intended partner, Yang Guang, failed to mate. By August, the zoo announced she was showing signs of pregnancy and could give birth at the end of that month. But she has now returned to the behavioral patterns and eating habits of a non-pregnant panda.

"Such a loss has always been in our minds as a very real possibility, as it occurs in giant pandas as well as many other animals, including humans," Chris West, chief executive for the Royal Zoological Society of Scotland, told the BBC. “We are conducting a detailed review of the scientific data collected, but I am totally confident that we did everything it was possible to do."

The zoo is renting Tian Tian and male panda, Yang Guang, from China for around £600,000 a year, or close to $1 million, hoping a cub or cubs would bring in more visitors.