Here are some key elements:
* The "Nightingales" are symbolic: The nightingales in the poem are not the traditional symbols of love and fertility. They are described as "jug-jug" and "sprawling out upon the grass" (lines 15-16), evoking an image of death and decay rather than life and creation.
* The "Shape" and "the eyes that fix you in the chair" (lines 1-2): The poem begins with an unsettling presence, suggesting a force that paralyzes and hinders. This "shape" could be interpreted as representing Sweeney's own inner anxieties and incapacities.
* The "dark" and "shadow" imagery: The poem is infused with imagery of darkness, shadows, and decay. These themes are consistent with a sense of sterility and the absence of vitality.
* The fragmented and disjointed narrative: The poem's fragmented and disjointed structure, filled with stream-of-consciousness, reflects a sense of alienation, isolation, and a lack of connection, potentially including the absence of a connection to procreation or a family life.
* Sweeney's "empty" state: There are multiple instances where Sweeney is described in terms of emptiness and lack. He is "empty" (line 32) and "has no eyes" (line 58). This emptiness can be interpreted as representing a lack of emotional connection, a void where a potential for life could be.
It's important to note that T.S. Eliot's poetry often relies on symbolism and ambiguity, leaving room for various interpretations. While infertility might not be explicitly stated, the poem's thematic elements suggest an absence of life, fertility, and the potential for creation.