The Collaborative International Dictionary of English v.0.48:

Proeguminal \Pro`e*gu"mi*nal\, a. [Gr. ?, p. pr. of ? to lead
   the way: cf. F. pro['e]gum[`e]ne.] (Med.)
   Serving to predispose; predisposing; as, a proeguminal cause
   of disease.
   [1913 Webster]