By the way, if you install Pandoc and reload Scrivener, you will find a new set of Markdown export formats added to your Compile for drop-down menu, at the very bottom. Pandoc → DOCX is one of the, which would save you the step of having to load the .md file in another software, and then use its interface to export again to another file type.
Pandoc’s DOCX files have proper heading styles as well, so you’d get a structured document in a word processor. Perhaps you prefer iA Writer’s output though, there are plenty of options out there for the step of turning .md files into end documents. But I figured I’d mention that you can reduce this down to one-click in Scrivener if that’s of value to you.
Also, just for the sake of any future readers—you do not have to switch to using RTF as a writing style if you want to avoid the use of Markdown-style double-spaced paragraphs while writing. It only takes a few switches in the compile settings to enable paragraph spacing conversion. This post was written to someone writing LaTeX instead of Markdown in Scrivener, but for the purposes of changing word processing-style paragraphs to plain-text style paragraphs, there is no difference in the 2-step procedure described in that post.