People.com said, according to the unidentified source, nearly 80 guests attended Saturday's baby shower at the Kardashian family home to offer congratulations to the "Kourtney and Khloe Take Miami" star.
"It was a huge success," the source said.
Among those in attendance was Kardashian's mother, Kris Jenner, and her sisters Khloe, Kim, Kylie and Kendall.
Kim Kardashian remarked about her 30-year-old pregnant sister's appearance while planning the baby shower with event planner Sharon Sacks, People magazine said.
"She's a really cute pregnant girl. It's just a big belly," Kim Kardashian, 29, said.
The child will be the first for Kourtney Kardashian and her boyfriend, Scott Disick. The former "Keeping Up with the Kardashians" star is due in December.