There is a pain so utter — Childbirth

There is a pain－so utter－¹
It swallows substance up－
Then covers the Abyss with Trance－
So Memory can step
Around－across－upon it－⁵
As one within a Swoon－
Goes safely－where an open eye－
Would drop Him－Bone by Bone.

(F.515/J.599)

[1] pain:: pain of childbirth; pain of raising a child.
[2] swallows substance up:: to support the growing of the baby.
[3] Abyss:: a bottomless depth, the mother's devotion to the child. Trance:: the half-conscious state of how the mother feels about her child.
[4, 5] Memory, across:: of raising her son.
[7] open eye:: to see clearly her son's naughty or rebellious acts.