Just as mannequins cannot procreate, nor can their live counterparts risk their "perfection" by becoming pregnant. Plath suggests that perfection itself "tamps the womb," and goes on to describe the emotions she associates with menstruation, the cycles of menstruation symbolized by the moon.
Just as mannequins cannot have children, neither can their real-life counterparts risk losing their idealized beauty by getting pregnant. Sylvia Plath argues that perfection itself acts like a barrier, preventing women from experiencing motherhood. She connects menstruation to these cyclical themes, using the moon as a symbol for the natural rhythms of female bodies and emotions.