Throughout Fatal Attraction, we see the desperate measures that Alex will go to to get any type of attention or reaction from Dan after the affair is over.
Alex proceeds to tell Dan that she's pregnant and she gives him her gynecologists business card to call him.
There is also a scene depicting Dan rummaging through her apartment and he sees an E.P.T. pregnancy test in the medicine cabinet, but, it doesn't show anything else.
Dan admits to his friend that he did infact call the gynecologist.
Dan: So, you know what I did? I called the Doctor. Do you know what he says? Congratulations. I can't even imagine what she told him.
Is there any evidence that Alex actually is pregnant with Dan's child? We see the desperate measures that Alex resorts to throughout the movie. I would see it being completely feasible for her to create a phony business card with a fictitious Doctor. Wouldn't a phantom pregnancy be another one of her desperate measures?