title: A clinical evaluation of the ultrasonic sensor in obstetrical practice.
mesh_terms: D005069:Evaluation Studies as Topic; D005260:Female; D005318:Fetal Heart; D005865:Gestational Age; D006326:Heart Auscultation; D006801:Humans; D010920:Placenta; D011247:Pregnancy; D011877:Radionuclide Imaging; D014463:Ultrasonography; D014599:Uterus