title: Is second-trimester genetic amniocentesis for trisomy 18 ever indicated in the presence of a normal genetic sonogram?
authors.forename: Y
authors.initials: Y
authors.lastname: Oyelese
authors.forename: A M
authors.initials: AM
authors.lastname: Vintzileos
mesh_terms: D000649:Amniocentesis; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis*; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D014314:Trisomy / Q000175:diagnosis*; D016216:Ultrasonography, Prenatal; D019564:Unnecessary Procedures