The female panda was artificially inseminated for the third time in March this year.
Foetus thought to have been reabsorbed
The UK's only female giant panda, Tian Tian, will not give birth to a cub this year, Edinburgh Zoo experts believe.
Hopes were raised early last week when the pandas' outdoor viewing area was closed due to the possible arrival of a cub.
However, experts now say the foetus may have been reabsorbed into the womb in the late stages of pregnancy. Resorption is thought to be a common occurrence in giant pandas.
“Based upon our scientific data, the window has now passed during which Tian Tian would have given birth," said Chris West, CEO of the Royal Zoological Society of Scotland (RZSS).
"Therefore RZSS has to advise that we now do not believe that our female giant panda will have a cub.
“Tian Tian is still showing behaviour of a pregnant panda, being sleepy and off her food, but we now must assume she has resorbed her pregnancy in late term."
The female panda was artificially inseminated for the third time in March this year. In 2013, she is thought to have lost her cub late term, while last year keepers reported late reabsorption of the foetus could have occurred.
The news comes after the surprise birth of twin panda cubs at Washington National Zoo last weekend, followed by the birth of a female cub in Malaysia, which was announced on Monday.
Nonetheless, Edinburgh Zoo says it has carried out the world's most comprehensive hormone analysis of a female giant panda, making key discoveries about giant panda pregnancy which it hopes will add to the global understanding of the species.
The pandas' outdoor viewing area reopened to the public today (25 August).
Image courtesy of RZSS