The museum announced last month that a wolf that's given birth to pups in the past was showing signs of being pregnant again.
But now officials say - while they're still holding out hope - they believe the animal is experiencing a pseudo pregnancy.
"The chances of having a litter are very low now," said Sherry Samuels, the Museum's animal department director, in a statement.
There are less than 300 red wolves in existence. The Museum of Life and Science is a member of a national network that houses red wolves as part of the Species Survival Plan, supervised by the American Zoo and Aquarium Association.