WASHINGTON (AP) Scientists at the National Zoo have detected rising hormone levels in the zoo's female giant panda.
This means Mei Xiang could either give birth in 40 to 50 days or come to the end of a false pregnancy. She was artificially inseminated in January.
Reproductive biologist Janine Brown says zoo keepers remain "hopeful, but cautious" that Mei Xiang is pregnant. Brown says the panda's hormone levels and behavior sometimes indicate she is pregnant when she's not.
Veterinarians are conducting weekly ultrasounds to look for a fetus. So far, they haven't seen any indication of one, but it's still too early. Panda fetuses don't start developing until the last weeks of a gestation period.
Mei Xiang gave birth to Tai Shan in 2005. He was sent to a breeding program in China earlier this year.
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