Paragraph.AutoAdjustRightIndent (Word)

True if Microsoft Word is set to automatically adjust the right indent for the specified paragraphs if you've specified a set number of characters per line. Returns wdUndefined if the AutoAdjustRightIndent property is set to True for only some of the specified paragraphs.

With Selection.ParagraphFormat 
 .AutoAdjustRightIndent = True 
End With