She told C magazine: "I had this condition called placenta accreta. There were a couple little operations to fix all that, so that created a little hole in my uterus, which I think made it really tough to get pregnant again.
"It was a long road. I would go to the doctor in Beverly Hills every day at five in the morning to get tested to see if I was ovulating."
The E! reality star says constantly checking if she was ovulating sucked "the fun out of" her and Kanye's attempts to get pregnant.
Kim is expecting her second baby in December, but the couple may not be able to have a third due to further fertility complications.
She admitted: "They think I'll have placenta accreta again, so if the placenta grows a little bit deeper than it did last time, then they are prepared to have my uterus removed, which is a little scary for me.
"I think we're just gonna go day by day, see how overwhelming it is, and see how the delivery goes."