The Hidden Positivity of Sylvia Plath's Metaphors

Plath's 1959 poem is a clear metaphor for pregnancy with lines like "a melon strolling on two tendrils", but it strikes me the entire work could be read as a positive mantra for life. "I'm on the train and there's no getting off", it's final line, feels like charging out into the world, being carried along by the forces of life, rather than anything overtly negative. Many of the phrases in the poem, while obtuse, grotesque even, could be considered corporate slogans.