Guy telling Mr. Nicklas he's a doctor
This early exchange between Mr. Nicklas, Rosemary, and Guy ironically foreshadows a number of plot elements. First, it suggests that Guy is willing to lie and perform in front of others—that his chosen vocation of acting will in fact spill over beyond his professional work. Second, it ironically anticipates the fact that Rosemary’s doctor (Dr. Sapirstein) will also be an “actor,” in that he manipulates Rosemary into not seeking treatment for her pregnancy pains and eventually sedates her into submission before giving birth.
Rosemary holding the silver coin in her palm
Rosemary informs Guy of her pregnancy by standing near the front door with a silver coin held in her outstretched palm. Her gesture is at once a symbolic indication that she is pregnant, and an ironic reference to the ritual significance of “silver” within the coven’s belief system. Rosemary will later remark that the Castevets own an alarming amount of “beautiful silver,” and Laura-Louise chastises Rosemary for placing a silver spoon in a cup of breast-milk.
Guy telling Roman, "That's showbiz" (situational irony)
Guy’s remark to Roman that all religions are merely “showbiz” is highly ironic, given that it provides an early and meaningful clue that the coven is staging a performance for Rosemary’s benefit. Guy and Roman are ostensibly talking about the venality of the Catholic Church, but in fact the comment also accurately describes the glitzy, superficial exterior that The Bramford projects in order to conceal its sinister goings-on.
Rosemary telling Guy, "It'll go away in a day or two."
Rosemary delivers this line to Guy with droll irony, exploiting the fact that everyone around her thinks her pain doesn’t exist so long as it remains unacknowledged by Dr. Sapirstein. The ironic distance between Rosemary’s shocking pain/weight loss and the indifference of the men around her highlights the primacy of male medical authority over a woman’s personal testimony.
Dr. Sapirstein telling Rosemary her baby died
When Rosemary awakens after giving birth, Dr. Sapirstein initially lies by telling her that the baby died due to an ectopic pregnancy. This ironically references an earlier scene in which Rosemary, upon feeling sharp pain in her abdomen, visits Dr. Sapirstein to ensure the pregnancy is not ectopic. Dr. Sapirstein scolded her then for thinking so, and then later blames her for allowing the ectopic pregnancy to have happened, symbolizing her hopeless, Catch 22-style position of powerlessness.
