These lines seem to act as evidence of a sort of brainwashing. Although the title suggests it is the woman who "Turns Herself into a Fish", the emotional turmoil of the poem makes it seem unlikely that the woman's heart is entirely in it. However, due to societal pressures on women to adhere to a certain identity, placed upone them both by men and by other women who accept these constraints, this woman may feel that this is what she is meant to do -- become merely a vessel for birth, devoid of feeling and thought, devoid of rights even. Even in submitting to this role, though, there comes the "chill pull" of something more.