title: Obstetrical ultrasound: an overview and update.
mesh_terms: D000649:Amniocentesis; D000013:Congenital Abnormalities / Q000175:diagnosis; D005260:Female; D005315:Fetal Diseases / Q000628:therapy; D005317:Fetal Growth Retardation / Q000175:diagnosis; D005323:Fetal Monitoring / Q000379:methods; D005328:Fetal Viability; D005865:Gestational Age; D006801:Humans; D010923:Placenta Previa / Q000175:diagnosis; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D014463:Ultrasonography