Value

Throughout the poem, pregnant women, and the children they carry, are compared to things of value. The speaker seems to feel as if she's been used to produce something, as nothing more than a cow bearing a calf, or a means to an end. The gist here is that a woman's value—especially in Plath's time—was often connected to her fertility.

• Line 4: All three things in this line are very desirable. Ivory and fine timbers may be more valuable than red fruit, but they are objects than can be purchased and used all the same. Then once you think of each object as valuable, think of them on the metaphorical level—each of these things is part of the riddle that ends up being about a pregnant woman. This means that the speaker is trying to talk about a pregnant woman through comparing her to valuable items. 
• Line 6: Money money money. This metaphor is comparing a pregnant woman and her baby to a purse fat with freshly minted (printed) money. Well, that's an awkward, insulting comparison. We see that this metaphor is referring to the baby because the money is new, as is the baby. The word purse, as we wrote earlier, could be referring to female genitals as well as something you put money in. This line continues the trend in this poem of writing of a pregnant woman as an object that can be bought and sold—a commodity of sorts.
• Line 7: This line shows that the speaker feels she is being used. She feels like she's just a means to an end, a stage that leads to a master plan, and, getting us back to value, a cow in calf. This metaphor compares an animal, a big old cow that's in calf, to a woman who's with child.