And after subsequent news outlets reported on the interview, Kim took to Twitter to clarify exactly what she meant on the nighttime talk show.
"I'm so tired of people twisting my words," she wrote.
"Khloé did start fertility and she wanted to have a baby, but I believe in the middle of the process she realized timing wasn't good based on what was going on with her relationship."
Kim added, "She was not ready to tell us everything so she stopped without telling us."
During the interview with Jimmy Kimmel, Kim said that she hopes it's "more understandable" now why Khloé and Lamar never had a baby.
"For so long, everyone in our family was feeling really sad for Khloé [and] thinking that she wasn't getting pregnant and everyone around her was," said Kim, who gave birth to North West in June 2013.
"She was not showing up to these doctors' appointments behind our back on purpose and doing everything on purpose [to not get pregnant]," the 33-year-old added.
"She knew that it wasn't right. She knew that she wasn't ready."
But Kim credits her big family for being there for her little sister through the trying times.
"When you have a really good support system, it can be easier," she explained. "It's never going to be easy, but it can be easier."
Catch new episodes of Keeping Up With the Kardashians, Sundays at 9 p.m., only on E!