The Collaborative International Dictionary of English v.0.48:

Obstetrician \Ob`ste*tri"cian\, n.
   One skilled in obstetrics; an accoucheur; especially, a
   physician who specializes in obstetrics.
   [1913 Webster]

WordNet (r) 3.0 (2006):

obstetrician
    n 1: a physician specializing in obstetrics [syn:
         obstetrician, accoucheur]

Moby Thesaurus II by Grady Ward, 1.0:

26 Moby Thesaurus words for "obstetrician":
   anesthesiologist, cardiologist, chiropodist, dermatologist,
   eye doctor, eye-ear-nose-throat specialist, geriatrician,
   gerontologist, gynecologist, immunologist, internist, neurologist,
   oculist, ophthalmologist, orthopedist, otolaryngologist, otologist,
   pathologist, pediatrician, pediatrist, podiatrist, psychiatrist,
   radiologist, serologist, skin man, specialist