WASHINGTON (WUSA) -- There's no word yet on whether the National Zoo's giant panda Mei Xiang is pregnant. Vets did conduct an ultrasound on Tuesday.

Zookeepers recently saw a jump in hormone levels that could indicated the panda is either pregnant or experiencing a "pseudopregnancy," which is when a panda ovulates but does not conceive.

Mei Xiang has had five pseudopregnancies since 2007. She gave birth to her only cub, Tai Shan, back in 2005.