Plath uses a number of poetic devices in this poem. These include apostrophe, which is a direct address of an absent person, animal, or thing. In this case, the speaker is talking directly to her mother, addressing her as "mother, mother."

Plath use the literary device of repetition in this poem. Repeating words such as "nod" and "always" brings emphasis to them but also adds the singsong rhythm of a nightmarish nursery rhyme to verses about the darker side of a girl's childhood.

Like repetition, the device of juxtaposition creates a dissonance between, for example, the baby in the crib, usually an idyllic image of innocence, and the disturbing words and images swirling around the baby that indicate something is off-kilter, such as "disfigured," "unsightly," "unwisely," and "unasked."

In the first stanza, Plath uses a simile when she writes of the muses at her crib as having "heads like darning-eggs." This describes the de Chirico painting called "The Disquieting Muses," which was the inspiration for the poem. But by likening the heads to darning eggs, ovals women would use to hold a sock in place to be mended, Plath gives these faceless figures an unsettling domestic association.

Plath employs alliteration to create a sense of rhythm and emphasis, such as in "nodding by night" with its repeated n sounds and the repeated b in the following:

Study windows bellied in
Like bubbles about to break.

Plath frequently employs imagery in the poem. For example, we can picture the idealized scene when the mother

fed
My brother and me cookies and Ovaltine.