(CNN) -- It's a sad day for Britain's panda lovers. After weeks of waiting, experts announced Tuesday that they no longer believe Edinburgh Zoo's female giant panda, Tian Tian, is pregnant.
Hopes had been high that Tian Tian, who has been on loan to the zoo for less than two years, might produce a panda cub to wow the crowds and help boost panda numbers.
But experts at the Royal Zoological Society of Scotland now think Britain's only female giant panda conceived and carried a fetus to late term but then lost it.
Chris West, chief executive officer for the Royal Zoological Society of Scotland, said officials were saddened by the turn of events.
"Timings are difficult to pinpoint at this moment, but we had a meeting this morning where Tian Tian's behavior and hormone results were reviewed and have come to the conclusion that it is very likely she has lost the pregnancy," he said in a statement.
Tian Tian has returned to normal eating and behavior patterns, he said. The creature's enclosure, which was closed to visitors to give privacy during the pregnancy, will remain shut to the end of the week.
"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," West said.
The zoo's scientists will review the data gathered, he said, but added that he is "totally confident that we did everything it was possible to do." The cub was conceived by artificial insemination.
Panda cubs in Atlanta, Washington
Although the bad news for Tian Tian is a blow for conservationists and panda fans, it's been a good summer for the black-and-white stars at zoos across the pond.
That birth came only a month after twin cubs were born at Zoo Atlanta -- the first set of panda twins born in the United States in 26 years.
The twins were the first for Lun Lun, who has two other offspring at that zoo, and were the product of artificial insemination as well. Their father is Yang Yang, also a resident at Atlanta's zoo.
The cubs have still to be named, following Chinese tradition.
CNN's Susannah Palk contributed to this report.