miscarriage vs unluck

miscarriage

noun
  • A failure; a mistake or error. 

  • The spontaneous natural termination of a pregnancy, especially before it is viable; the fatal expulsion of a foetus from the womb before term. 

unluck

noun
  • Absence or lack of luck; lucklessness; bad luck; misfortune. 

How often have the words miscarriage and unluck occurred in a corpus of books? (source: Google Ngram Viewer )