Computer-generated imagery
Several of the special effects used in the episode were created in a "low-stress" manner that did not rely wholly on Computer-generated imagery. During the childbirth scene, gas-burners were set a distance away from a fire-proof bed. The scene was then filmed with a long lens to give the effect that the fire was mere inches away from the bed. Producer John Shiban said that the film crew made "a big deal out of the eyes" to make the scene frightening. The devil sonogram was created by using the videotape of a real sonogram of a crew member's wife. The videotape was then edited to give it a demonic look.