PageSetup.GutterStyle (Word)

Returns or sets whether Microsoft Word uses gutters for the current document based on a right-to-left language or a left-to-right language. Possible return values are wdGutterStyleBidi - Bidirectional gutter should be used to conform to right-to-left text flow, wdGutterStyleLatin - Latin gutter should be used to conform to left-to-right text flow.

ActiveDocument.PageSetup.GutterStyle = wdGutterStyleBidi