The 27-year-old socialite, who has been married to the basketball player for over two years, is said to have visited the ART Reproductive Center in Beverly Hills on June 12 to discuss her options, reported Daily Mail.
"She's thrilled for Kourtney, but she's really sensitive. And it's hard to see your sister get something you want so badly," a source said.
The 'Keeping Up with the Kardashians' star has previously said she feels under pressure to have a baby.
"People keep saying, 'Why aren't you pregnant yet?' That's what scares me, when people are like, 'Did you go to the doctor? Do you know if everything's working? It's nerve-wracking. Sometimes I feel like I'm letting everyone down," she had said.