LONDON (Reuters) – Britain’s only female giant panda bear will not give birth this year, dashing hopes that she was about to produce the first panda cubs born in the country, Edinburgh Zoo said on Monday.

In August, the Scottish zoo had said it believed Tian Tian, which translates to Sweetie in Chinese, was pregnant but warned panda breeding was a complicated process.

“It is with sadness that we can confirm Tian Tian, Edinburgh Zoo’s resident female giant panda, will not give birth to cubs this year,” said Iain Valentine, director of giant pandas at the Royal Zoological Society of Scotland.

Tian Tian, born in 2003, is one of two pandas who moved to Britain from China under a 10-year loan. Whilst in China she gave birth to twins in 2009 but has failed to produce a cub since arriving in Scotland in 2011.

The foetuses of giant pandas are extremely small, making it hard for zoos to know whether females are pregnant.

The International Union for Conservation of Nature last year reclassified the species as “vulnerable” rather than “endangered”, citing growing numbers in the wild due to decades of protection efforts.