title: A new method of amniocentesis using ultrasound in multiple pregnancy to assess the second twin.
mesh_terms: D000649:Amniocentesis / Q000379:methods*; D000653:Amniotic Fluid / Q000032:analysis; D005260:Female; D006801:Humans; D008168:Lung / Q000196:embryology; D010713:Phosphatidylcholines / Q000032:analysis; D011247:Pregnancy; D011272:Pregnancy, Multiple; D013109:Sphingomyelins / Q000032:analysis; D014427:Twins; D014463:Ultrasonography
chemical_list: D010713:Phosphatidylcholines; D013109:Sphingomyelins