Sub Macro1()
Dim oLink As Hyperlink
Dim oRng As Range
    For Each oLink In ActiveDocument.Hyperlinks
        If oLink.Address Like "http*" Or oLink.Address Like "HTTP*" Then
            Set oRng = oLink.Range
            If oRng.Start = oRng.Paragraphs(1).Range.Start Then
                oRng.InsertBefore "URL: "
            End If
        End If
    Next oLink
End Sub