Edinburgh Zoo staff say Britain's only female panda continues to show positive signs that she is pregnant.
If Tian Tian is carrying a baby, the birth is expected to be in the next two weeks.
A team of keepers at the zoo have been given access to CCTV footage in their homes and the panda is being monitored around the clock for signs of labour.
Tian Tian and the zoo's male mate, Yang Guang, are the UK's only pair of giant pandas.
Results from the panda's urine samples are being analysed by Memphis Zoo and the China Conservation and Research Centre (CCRCGP) with both parties remaining "encouraged".
Tian Tian's progesterone levels continue to stay high and she is currently very sleepy, which are both positive pregnancy signs.
If the panda goes into labour, she will appear restless, start to bleat and her waters will break.
A zoo spokeswoman said it remained a "very sensitive period" for the panda if she were to be pregnant.
Tian Tian's body could yet reabsorb any foetuses.
Despite a lack of certainty, staff are planning for a birth to happen.
Chinese panda keeper Haiping Hu, from CCRCGP, arrived in Edinburgh on Saturday to be on hand if a cub or cubs are born.
Miss Hu has experience in assisting with panda births, especially if twins are born and one cub needs to be removed.
New incubators have also arrived and keepers are preparing a 24-hour rota to care for any newborns.
Iain Valentine, director of giant pandas for the Royal Zoological Society of Scotland, said: "What we are seeing in Tian Tian's hormones is encouraging, but we still cannot guarantee a pregnancy or successful birth.
"If indeed she is pregnant, this is an extremely risky time for panda pregnancies.
"Female giant pandas can actually reabsorb any foetuses or reject them if pregnant.
"If she is pregnant and carries to full term, we believe a cub or cubs could be born anytime over the next two weeks - although there are no certainties we must err on the side of caution and be on red alert from today."