labidometer

from The Collaborative International Dictionary of English v.0.48

Labidometer \Lab`i*dom"e*ter\, n. [Gr. labi`s, -i`dos, a forceps
   + meter: cf. F. labidometre.] (Med.)
   A forceps with a measuring attachment for ascertaining the
   size of the fetal head.
   [1913 Webster]