"There were so many times I thought I wasn't going to have the energy to see it through," she told the BBC Radio 4's "Front Row" show. "I was so fed up making it."
Bush said it was difficult balancing work with raising her son Bertie, 7.
"I felt my work could wait, whereas his growing up couldn't," she said in the taped interview airing Friday.
Bush also admitted she is "horrible to work with" in the studio.
"I'm very opinionated," she said. "I'm so fussy and picky. What's good is that I know what I want. It's when you don't know what you want when you're in trouble."
Bush's album hits British store shelves Nov. 7 and Nov. 8 in the United States.