The 12-year-old panda lost the cub after 128 days of gestation.
The medical team and Chiang Mai Zoo's executives announced at a news conference that the panda's pregnancy was confirmed but yesterday part of the dead embryo was found to have slipped out of the animal's body, while the animal's behaviour has returned to normal both for hormone levels and eating habit.
The reason for losing the cub is still unknown but it was thought that some part of the embryo was absorbed back into Lin Hui's body, ending the pregnancy.
The medical team and the zoo's executives thanked everyone for their moral support over such a loss and said the team have not lost hope for the panda's next gestation.
Lin Hui and her mate Chuang Chuang, on loan from China, produced their first cub 'Linping' in 2009, thanks to artificial insemination. Linping was sent to China for a year in September to find a mate.