I created a screenplay using MS Word. The layout has to match a specific format. When I print directly from Word it's perfect. When I create a PDF the line spacing decreases to where three extra lines fit on a page.
Normally I would simply print from Word but online screenplay competitions require a PDF. Can the line spacing be adjusted?
It sounds like what you might be seeing is not line-spacing changes but reflow. WORD does this based on the printer attached. For a while with WORD 2007 they disabled this and then put it back. If you access the printers in WORD and change to the Adobe PDF printer, you should see the reflow of the document that is similar to what you are seeing in Acrobat. If that is the case, reformat your document while having the Adobe PDF printer attached. If you prefer, you might be able to dig into the options in WORD and find the "use printer metrics" checkbox and uncheck it.
Keep in mind that WORD is not a layout program and the reflow is common to word processors, not layout programs.