"We’re thrilled about the possibility of a fourth cub for Lun Lun, but we remain cautiously optimistic at this point. Giant panda cubs are extremely fragile, and the chance remains that the fetus does not go to term."
Lun Lun, who was artificially inseminated in March, expects to give birth in 2 or 3 weeks if everything goes well. Her cub would be the first giant panda to ever be born in the United States in 2013.
According to an ultrasound done earlier this week, the fetus is currently 1.08 centimeters long.
Before moving the to Zoo Atlanta, Lun Lun lived in Chengdu and her birth name was Hua Hua. She was was renamed by a Taiwanese rock star, Su Huilun, who "adopted" her at the Chengdu Research Base of Giant Panda Breeding.
2014: The Year in Music [PHOTOS]