An Etymological Dictionary of the German Language/Annotated/schwanger

by Friedrich Kluge

schwanger, adjective, ‘pregnant, teeming,’ from the equivalent Middle High German swanger, Old High German swangar; compare Dutch zwanger, ‘pregnant,’ but Anglo-Saxon swǫngor, ‘awkward, idle’; the latter meaning makes the derivation from schwingen improbable. Anglo-Saxon has also the curious form swǫncor; see schwank.