Sub Demo()
Dim sWdth As Single, Shp As Shape, Rng As Range, i As Long
With ActiveDocument
  For i = .OMaths.Count To 1 Step -1
    Set Rng = .OMaths(i).Range
    With Rng
      .Collapse wdCollapseEnd
      sWdth = .Information(wdHorizontalPositionRelativeToTextBoundary)
    End With
    Set Rng = .OMaths(i).Range
    With Rng
      sWdth = sWdth - .Information(wdHorizontalPositionRelativeToTextBoundary)
      .CopyAsPicture
      .Text = vbNullString
      .PasteSpecial DataType:=wdPasteEnhancedMetafile
      Set Shp = .ShapeRange(1)
      With Shp
        sWdth = (.Width - sWdth) / 2
        .PictureFormat.CropLeft = sWdth
        .PictureFormat.CropRight = sWdth
        .WrapFormat.Type = wdWrapTopBottom
        .LockAnchor = True
      End With
    End With
  Next
End With
End Sub