childbearing vs lying-in

childbearing

adj
  • Of, pertaining to, or suitable for childbirth 

noun
  • The process of giving birth; pregnancy and parturition 

lying-in

adj
  • of, or relating to childbirth or postpartum confinement 

noun
  • The final stages of pregnancy; accouchement. 

  • A period of postpartum confinement, typically a month or longer, formerly common in Europe and still practiced in some parts of the world. 

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