(National Zoo/Mei Xiang’s den was closed Sunday to provide a quiet area for the potentially pregnant panda.)

Anticipation appears to be growing at the National Zoo, where officials closed the giant panda habitat on Sunday to keep a quiet area around possibly pregnant giant panda Mei Xiang.

Mei Xiang was inseminated artificially March 1, inaugurating a suspenseful waiting period.

On Sunday, the zoo made this announcement, suggesting that matters were progressing toward a conclusion sooner rather than later:

“The David M. Rubenstein Family Giant Panda Habitat will be closed to keep a quiet area around female giant panda Mei Xiang’s den who is exhibiting signs of pregnancy or pseudopregnancy.” Pseudopregnancy is a false pregnancy.

The zoo said its other giant pandas, Tian Tian and Bei Bei, could be viewed in their outdoor yards each day until 2 p.m.

Only ultrasound testing can confirm that a giant panda is pregnant. As of last week, the zoo said, no confirmation had been provided.

Ultrasound is the only sure way to tell whether a giant panda is pregnant before an actual delivery. (National Zoo photo)

But, the zoo said, Mei Xiang has apparently had the hormone increase that is consistent with both pregnancy and false pregnancy.

This increase, which is a secondary rise for the panda, indicates that Mei Xiang “will either give birth or experience the final stages of a pseudopregnancy within the next month,” the zoo said Thursday.

In addition, the zoo said in its latest announcement, she is showing the behavior pattern expected after the hormone increase. “She is building a nest in her den, has a decreased appetite, is sleeping more and is reacting to loud noises,” it said.

So, the zoo indicated, it will hope for the best. And do what it can. Including the hanging on the den door of a figurative sign saying, “Do not disturb.”