“cause-for-oath.” The Hebrew is “oath,” but in this context the woman does not become an oath, but the reason that the oath exists; to root out evil. (cp. Fox, The Schocken Bible).
“your thigh fall away and your body swell.” The meaning of this Hebrew phrase is not understood, and there have been many suppositions set forward as to what it means. It is fairly clear that “thigh” is used here as a euphemism for the woman’s genital organs. The “thigh” was used euphemistically for the genital organs, (see commentary on Gen. 24:2). [For more information on sexual euphemisms, see commentary on Isa. 47:2].