title: L/S ratios in twin pregnancy.
mesh_terms: D000653:Amniotic Fluid / Q000032:analysis; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D010713:Phosphatidylcholines / Q000032:analysis*; D011247:Pregnancy; D011272:Pregnancy, Multiple; D011296:Prenatal Diagnosis; D012127:Respiratory Distress Syndrome, Newborn / Q000175:diagnosis; D013109:Sphingomyelins / Q000032:analysis*; D014427:Twins
chemical_list: D010713:Phosphatidylcholines; D013109:Sphingomyelins