travail vs work one's fingers to the bone

travail

noun
  • Arduous or painful exertion; excessive labor, suffering, hardship. 

  • Specifically, the labor of childbirth. 

verb
  • To toil. 

  • To go through the labor of childbirth. 

work one's fingers to the bone

verb
  • To work especially hard, usually for an extended period. 

How often have the words travail and work one's fingers to the bone occurred in a corpus of books? (source: Google Ngram Viewer )