maternity vs pregnancy

maternity

noun
  • The state of being pregnant; pregnancy. 

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

  • The state of being a mother; motherhood. 

pregnancy

noun
  • The condition of being pregnant; an instance of this. 

  • The progression of stages from conception to birth. 

  • The period of time this condition prevails. 

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