antepartum vs prenatal

antepartum

adj
  • Describing the period before childbirth; antenatal 

prenatal

adj
  • Being or happening before birth. 

noun
  • A dietary supplement to be taken by somebody expecting to give birth. 

  • A person who is expecting to give birth. 

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