Why is InDesign adding hundreds of pages to my book?

I'm creating a book in InDesign. I have individual chapters saved as Word Docs. To make a new chapter, I make a copy of one of my chapters, delete the text, and then place the new chapter. That way I have the Parents I need and the Paragraph and Character Styles. It was working fine for a while, but now, for reasons I can't understand, every time I add a new chapter (the Word doc might have 7 pages), as soon as I place text it adds a huge number of pages. Sometimes it's 50 or so, once it was over 200. I have to then go and delete those pages. I've tried using different chapters to copy, I've tried making a template out of one, doesn't matter. Hundreds of added pages every time I place. Why? How can I stop it?