amma vs maternity

amma

noun
  • mother 

  • An abbess or spiritual mother, especially one of the Desert Mothers. 

maternity

noun
  • The state of being a mother; motherhood. 

  • The state of being pregnant; pregnancy. 

  • A ward or department in a hospital in which babies are born. 

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