Taking to her social media account, the 'Keeping Up with the Kardashians' alum shut down the swirling rumours, reports aceshowbiz.com.
Kourtney posted a racy photograph of herself swimming in a pool in a purple bikini with Travis Barker.
In the picture, the mother-of-three could be seen packing on some PDA with her fiance.
"Life with you," she simply captioned her post.
In the comment section, one of her fans left a comment that read: "Not to be that girl but is that a preg belly."
The message led a frustrated Kourtney to clap back: "Are we really gonna do this every time I post a photo?"
Prior to this, it's reported that Kourtney, who shares 10-year-old Mason, 7-year-old Penelope and 5-year-old Reign with her former partner Scott Disick, would "love nothing more than to have a baby together" with Barker.
It's also said that the soon-to-be-married couple, who got engaged at the Rosewood Miramar in Montecito, California on October 19, was hoping to be "expecting" by next year.
"Kourtney has always wanted another baby and never felt like she was done. Now that she's with Travis, she wants it even more," a source said in October.
Another source shared that the Kardashian-Jenner family wholeheartedly supports the lovebirds to have a baby as they stepped on a new level in their relationship.
The source said: "They are both really great parents and enjoy spending time with their families."
The so-called inside source added that Barker "has been known to be such an amazing dad, so it seems like the natural thing for them to do."
"Ideally, Kourtney would like a natural birth. She's confident it won't be a problem because she's always been lucky to conceive naturally and has taken great care of herself physically," the source claimed.
"Certainly though, she and Travis want to bring their own child into the picture, and if she can't conceive, they'll look at other alternatives. He's been so kind and gracious to her and Scott's (kids) too."