"I find it disturbing that society loves to critique a woman's shape no matter how beautiful or happy she may be within herself," Khloe writes, noting she's been herself prone "to public attacking in regards to my body or appearance.
Khloe wrote anyone who dares to "criticize a woman who is growing another life inside of her is true scum in my eyes," noting that this should be the "most memorable and beautiful" time of her sister's life, as she's carrying boyfriend Kanye West's child.
"I would hurt for her for years if all she remembers is the pain and emotional abuse she has received from so many vicious people," Khloe wrote, telling the haters to "stop being so careless with your words.
"Kim, you may be one of the strongest people I know. I have no idea how you endure such abuse but still smile and shine everyday! I commend you for not putting your head down and going into hiding like so many would."
"I wish you could see how you have this pregnant glow and you sparkle everyday!" Khloe wrote at the end of the post. "I couldn‘t be prouder to be your sister!!!
Kim, who's expecting her first child with the rapper this summer, responded with the caption, "I Love You So Much Khloe!"
As we previously reported, News of Kim's pregnancy leaked during Kanye's concert at Atlantic City's Revel Resort in Dec. 2012, when the rapper called Kim "my baby mama" during the show, and proclaimed, "Now you having my baby!"