Religion
Rosemary's Baby is a pointed critique of the Catholic Church's restrictive attitudes surrounding a woman's bodily autonomy. The film plays on Rosemary's fears as a Catholic, as well as the Catholic Church's fear of women. Rosemary's Catholicism shapes her way of thinking and perceiving—nuns and priests populate her dreams, and she grows uncomfortable at Roman's suggestion that the Pope is unworthy of respect. Catholic beliefs about reproductive rights pervade the film, such as when Rosemary cries "I won't have an abortion!" despite her sharp pain, as do stereotypes surrounding Catholic families, such as when Rosemary tells Minnie she has over a dozen nieces and nephews. Minnie's more forward, New York-style way shocks Rosemary's more conservative, Catholic sensibilities. Throughout the film Polanski connects the ritualism of religion to the ritualism of theater, such as when Roman calls all religions "showbiz."
Performance
Performance, acting, and stagecraft are all central to the film, both literally and symbolically. The Bramford is immediately established as a haven for actors and theater professionals, and it supplies the setting for a story in which a coven with ties to the theater industry work together to cannily manipulate an actor's wife. Rosemary deduces that the coven lures Guy by promising him choice roles in Hollywood—so long as he fulfills his "role" in their plot to have Rosemary conceive the son of Satan. And by collectively deceiving Rosemary about their plans, all of the coven members are essentially actors staging a production for Rosemary's benefit. References to actors and acting abound, such as when Roman mentions Helena Modjeska, or when Rosemary watches a Busby Berkeley-style musical on television. Polanski also frames Rosemary's rape as a spectacle or performance, having a woman with old Hollywood glamour descend a staircase and prime Rosemary for her "role."
Gender
Rosemary's Baby adheres to the conventions of Gothic narrative, which often exploit the rift between male and female domains of experience in order to generate thematic dread, terror, and suspense. Gothic narratives often pit curious, intrepid heroines against ambiguously evil men in a mansion or castle-like setting, such as Daphne du Maurier's Rebecca. Polanski shows Rosemary consoling Guy in sulky moods, and enduring his condescending, infantilizing gestures, such as his spanking her. It is not until Rosemary's female friends corner her in the kitchen at her party and block Guy out that she is able to tell her story to a trusting audience. Polanski symbolizes Rosemary's womanhood with flowers and floral imagery, and uses satanism as a metaphor for Guy's marital rape. Rosemary's short haircut likely indicates a desire on her part to flout the gender roles and conventions that have been foisted upon her during the process of pregnancy and childbirth.
Evil
Evil is a vital theme coursing through the film, sometimes lurking beneath the surface and sometimes plainly visible. Hutch supplies a kind of abbreviated history of evil in The Bramford, telling Guy and Rosemary about the Trench Sisters (who cannibalized children) and Adrian Marcato, a devil worshipper. In their haste and eagerness to be part of an ultra-exclusive residence, Guy and Rosemary ignore Hutch's warnings. The Tannis charm symbolizes evil, containing a foul-smelling mold or fungus called "Devil's Pepper." By showing the Pope wearing the Tannis charm in Rosemary's dream, Polanski paints the Catholic Church as evil. Minnie and Roman serve a thick steak to Rosemary and Guy that hints at the blood-and-flesh sacrifice that their coven practices. The black bassinet at the end of the film has an upside-down crucifix hanging inside of it, indicating that it carries the antichrist. The TIME Magazine cover Rosemary reads ("Is God Dead?") suggests a world in which evil has run amok.
Purity
Raised Catholic in Omaha, Nebraska, Rosemary has no qualms about being a homemaker and performing traditional wifely duties, like making her husband dinner and renovating their domestic space, making her an avatar of traditional motherhood. The purity and integrity of Rosemary's body is constantly under siege by outside forces. Over the course of the film, she is clawed, raped, sedated, made to drink vitamin mixtures, made to eat chocolate mousse, made to take pills, made to pump breast milk, and made to endure indescribable pain. The coven systematically siphons away her control over her own body, until they can finally ensure that she carries the son of Satan to term. Rosemary's dreams expose her Catholic fears about lapsing from a pure state, such as when a nun berates her, when her breasts are exposed in public, and when she ascends the Sistine chapel. Ironically, Rosemary's passivity and obedience, inculcated in her by her Catholic upbringing, are the traits that leave her vulnerable to the workings of a satanic cult.
Secrecy
Secrecy—and its counterpart, disclosure—are key to the plot and imagery of Rosemary's Baby. The Bramford itself is naturally secretive, given that it is a highly exclusive and private residence. The symbol of the secretary blocking the hall closet exemplifies secrecy and concealment as well, given that it is a piece of furniture designed to enclose items, blocking a closet itself designed to enclose items, which in fact conceals a secret passage. These stacking layers of concealment suggest the complexity and opaqueness of the plot that the coven will set in motion against Rosemary, which it takes her several months to untangle. What little agency Rosemary wields often must be done in secret, such as when she dumps Minnie's mousse in her napkin, pours out her vitamin drink, or stashes her pills in her bed-frame. The porousness of the walls separating the Woodhouse and Castevet apartments also suggests the gradual disclosure of a secret: at the beginning of the film, Rosemary and Guy can hear chanting through the partition, and by the end of the film, the Castevets have come charging into the apartment with the coven in tow.
Sexuality
Rosemary's Baby is a Gothic tale that exploits traditionally feminine fears about violation and helplessness. Polanski establishes Guy as a playfully dominant husband, flirtatiously spanking Rosemary in public, but waiting for her to initiate sex in their first love scene together. After he joins the coven, however, Guy not only rapes Rosemary while she is unconscious, but blames her for getting too drunk on "baby night." The supernatural horror of the scene (in which Satan himself impregnates Rosemary) disguises what is in fact a very real, violent instance of marital rape. Guy's defenses (that she got too drunk, that he didn't want to miss "baby night") subtly lay the blame on Rosemary's shoulders for allowing herself to be in that compromising position, offering the kind of victim-blaming logic that defense attorneys often use when defending alleged rapists. Rosemary's hallucination in which she confesses to the Pope while being raped suggests that her Catholic upbringing has left her bereft of any meaningful sexual autonomy.
