impregnate (v.)

c. 1600, "to fill with an ingredient, spirit, etc.;" 1640s as "make (a female) pregnant), from Late Latin impraegnatus "pregnant," past participle of impraegnare "to render pregnant," from assimilated form of in- "into, in" (from PIE root *en "in") + praegnare "make pregnant" (see pregnant). Earlier in same sense was impregn (1530s), which OED marks as "now only in poetic use."