title: Localization of the cervix in ultrasonic placentography with the use of a fluid-filled pessary.
mesh_terms: D002584:Cervix Uteri; D005260:Female; D005865:Gestational Age; D006257:Head / Q000196:embryology; D006801:Humans; D010920:Placenta; D010923:Placenta Previa / Q000175:diagnosis; D011247:Pregnancy; D014465:Ultrasonics; D001743:Urinary Bladder / Q000196:embryology; D014867:Water
chemical_list: D014867:Water