https://www.imdb.com/title/tt0137523/trivia/?item=tr0755880

The original "pillow talk"-scene had Marla saying "I want to have your abortion". When this was objected to by Fox 2000 Pictures President of Production Laura Ziskin, David Fincher said he would change it on the proviso that the new line couldn't be cut. Ziskin agreed and Fincher wrote the replacement line, "I haven't been fucked like that since grade school". When Ziskin saw the new line, she was even more outraged and asked for the original line to be put back, but, as per their deal, Fincher refused.

Also, the actress didn't know grade school in the US is 6-12 years old as she is from outside the US. She didn't find out until afterwards and was very unhappy about saying it.