title: Placental ultrasonic appearance.
mesh_terms: D005260:Female; D005325:Fetal Organ Maturity; D006801:Humans; D007231:Infant, Newborn; D008168:Lung / Q000196:embryology*; D010713:Phosphatidylcholines / Q000032:analysis; D010920:Placenta / Q000033:anatomy & histology* / Q000473:pathology; D011247:Pregnancy; D011336:Probability; D013109:Sphingomyelins / Q000032:analysis; D014463:Ultrasonography
chemical_list: D010713:Phosphatidylcholines; D013109:Sphingomyelins