Following the birth of sister Kim Kardashian's daughter North, American OK magazine has claimed that Kourtney has told friends she's pregnant again and is "very excited" about welcoming another addition to her family.
A source told the mag: "Kourtney has confessed she's expecting. She's very excited and only telling a select few right now - but she just couldn't keep it quiet any longer.
"Kourtney has that kind of glow she had with Mason and Penelope... they wanted to have one right after Penelope."
They went on to add that Kourtney did not drink any alcohol during a trip to Miami, despite attending a runway show sponsored by a vodka brand.
It is thought that Kourtney and Scott had "always planned" to have a baby after Penelope, but after Kimmy gave birth to North - or Nori for short - they started trying again.
The source added: "When Kourtney first held Nori, a huge look passed between her and Kim, who turned to Scott and joked, 'Uh-oh'. Scott knew exactly what she was thinking - 'They would be next'."
Both Kourtney and Scott are yet to comment on the baby rumours.