Sentence:  Which gave the sons of England birth / Had felt their blood upon her brow, / And shuddering with a mother's <WSD>throe</WSD> / Had turned every drop of blood / By which her face had been bedewed / To an accent unwithstood, &mdash; / As if her heart had cried aloud: [...] 
Meaning of the word marked with <WSD> tags:  A pang, spasm.