
When you import (or export) a Word document, the layouts in Pages and MS Word are not identical. Some things do not simply transfer, as described here.
However, even when all present document features are supported in both programs, the layout may differ.
Text that fits on one page in one application may not do so in the other. Still, all the metrics is the same: font, font size, line spacing, character spacing, and so on.
If you look closely on the picture above, you will see that the characters have the same height in both applications, but the space between the lines is slightly off.
My guess is that this is for the historical reasons described in this article. MacOS and Windows calculate the line height in slightly different ways. MacOS uses the variables Ascender, Descender and LineGap, while most Windows applications use usWinAscent and usWinDescent. The variables mean almost the same thing, but not quite. There is more information in this article from Adobe.
MS Word needs to be 100% compatible with the layout of Word for Windows. It is MS Word, after all. And Pages clearly needs to use the MacOS way of doing things. The result is that the lines do not have exactly the same height.








