Kim Kardashian Wants to Know What Constitutes a ‘Baby Bump’

If anyone is used to pregnancy rumors, it's Khloé Kardashian.

Following a summer of major "baby bump" speculation, the reality star, 26, is facing it yet again, with new reports surfacing Monday.

"She's pregnant like every other week," Khloé's sister Kourtney Kardashian told PEOPLE coyly on Monday while promoting her new series, Kourtney & Kim Take New York.

Neither Kourtney nor sister Kim Kardashian would address the subject directly. Kim instead jokingly asked, "What I want to know is what constitutes a 'baby bump?' "

Kourtney suggested, "It's like if you eat a lot that day and sit down and have a tiny fat roll – it's so funny."

But despite the banter, a source close to the reality TV family says Khloé and her hubby Lamar Odom, 31, dismiss the latest rumors. "She's not pregnant yet," the source tells PEOPLE.

The sisters' new show airs Jan. 23 on E!. Khloé and Odom, meanwhile, have a reality show of their own in the works.