Twins discordant for Down's syndrome.
D000328:Adult; D000649:Amniocentesis; D003937:Diagnosis, Differential; D004200:Diseases in Twins; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D005333:Fetus / Q000033:anatomy & histology; D006257:Head / Q000033:anatomy & histology; D006801:Humans; D007746:Labor Presentation; D011247:Pregnancy; D011296:Prenatal Diagnosis; D014429:Twins, Dizygotic; D014465:Ultrasonics