The Collaborative International Dictionary of English v.0.48:

Menstruate \Men"stru*ate\, a.
   Menstruous. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Menstruate \Men"stru*ate\, v. i. [imp. & p. p. Menstruated; p.
   pr. & vb. n. Menstruating.]
   To discharge the menses; to have the catamenial flow.
   [1913 Webster]

WordNet (r) 3.0 (2006):

menstruate
    v 1: undergo menstruation; "She started menstruating at the age
         of 11" [syn: menstruate, flow]