The Collaborative International Dictionary of English v.0.48:

Obstetrics \Ob*stet"rics\ ([o^]b*st[e^]t"r[i^]ks), n. [Cf. F.
   obst['e]trique. See Obstetric.]
   1. The science of midwifery. [archaic]
      [1913 Webster]

   2. The branch of medicine that deals with childbirth or the
      care of women in parturition, or in the trouble incident
      to childbirth.
      [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

obstetrics
    n 1: the branch of medicine dealing with childbirth and care of
         the mother [syn: obstetrics, OB, tocology,
         midwifery]