stretch mark vs striae distensae

stretch mark

noun
  • Any of a series of red, irregular stripes on the surface of the skin caused by rapid growth of the tissues lying just underneath. They usually appear as a result of pregnancy, puberty or obesity, but can also be caused by rapid muscle growth. 

striae distensae

How often have the words stretch mark and striae distensae occurred in a corpus of books? (source: Google Ngram Viewer )