infancy vs unborn child

infancy

noun
  • The state of being an infant. 

  • An early stage in the development of anything. 

  • The state of being a minor. 

  • The earliest period of childhood (crawling rather than walking). 

unborn child

noun
  • A human offspring that is developing in the uterus; fetus. 

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