Giant panda Ying Ying, who was due to give birth to Hong Kong’s first giant panda cub, has suffered a miscarriage.

Ying Ying’s pregnancy was confirmed in late September and she has since been closely monitored for signs of labour.

However, ultrasound scans conducted on Tuesday and Wednesday showed that the foetus no longer had a heartbeat.

Doctors at the Ocean Park amusement park said they are very disappointed as they have been trying for four years to get Ying Ying pregnant.

The scans “clearly showed the foetus that we had been monitoring had stopped developing and the foetal structures were no longer distinct, thus confirming it is no longer viable,” said Ocean Park vet Dr Lee Foo Khong.

Earlier this year, 10-year-old Ying Ying mated naturally and was also artificially inseminated.

However, the staff at Ocean Park are unsure which method resulted in the successful pregnancy.

The 100kg female – described by the park as “inquisitive, active and vigilant” – attempted to mate naturally with two male pandas on five different occasions and one of the attempts was deemed successful.

But to improve the chances of a viable pregnancy, Ying Ying was also artificially inseminated.

Panda reproduction is a notoriously difficult process, with females only ovulating once a year.

It is also common for giant pandas to re-absorb the foetus into the womb in the late stages of pregnancy, “especially for first-time mothers due to their inexperience,” said Dr. Wang Chengdong of the China Conservation and Research Centre for the Giant Panda.

The gestation period is typically five months and one or two cubs are usually born.

Ocean Park, along with Wolong specialists, will continue to closely review the data gathered during the pregnancy in an effort to learn more about giant panda miscarriages.