The Collaborative International Dictionary of English v.0.48:

Pregnant \Preg"nant\, a. [L. praegnans, -antis; prae before +
   genere, gignere, to beget: cf. F. pr['e]gnant. See Gender,
   2d Kin.]
   [1913 Webster]
   1. Being with young, as a female; having conceived; great
      with young; breeding; teeming; gravid; preparing to bring
      forth.
      [1913 Webster]

   2. Heavy with important contents, significance, or issue;
      full of consequence or results; weighty; as, pregnant
      replies. " A pregnant argument." --Prynne. " A pregnant
      brevity." --E. Everett.
      [1913 Webster]

   3. Full of promise; abounding in ability, resources, etc.;
      as, a pregnant youth. [Obs.] --Evelyn.
      [1913 Webster]

            Wherein the pregnant enemy does much. --Shak.
      [1913 Webster]

   Pregnant construction (Rhet.), one in which more is implied
      than is said; as, the beasts trembled forth from their
      dens, that is, came forth trembling with fright.
      [1913 Webster]