title: Down's syndrome: current screening techniques.
abstract: Antenatal screening for Down's syndrome traditionally relied upon performing amniocentesis for karyotype on pregnant women aged 35 years and older. This method detects approximately 20% of all Down's syndrome pregnancies, with a false-positive rate of 4.3%. By incorporating maternal serum alpha-fetoprotein values as an additional screening parameter to maternal age, 28% of all Down's syndrome pregnancies may be diagnosed, with a 35% reduction in false-positive results. Other screening parameters such as maternal serum unconjugated estriol and human chorionic gonadotropin may eventually make it possible to detect more than 65% of pregnancies with chromosomally abnormal fetuses, without compromise in false-positive rates.
authors: Department of Obstetrics and Gynecology, George Washington University Medical Center, Washington, DC.
authors: R S
authors: RS
authors: White
mesh_terms: D000649:Amniocentesis; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis*; D005189:False Positive Reactions; D005260:Female; D005315:Fetal Diseases / Q000097:blood / Q000175:diagnosis*; D006801:Humans; D008423:Maternal Age; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods* / Q000592:standards; D011336:Probability; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D012307:Risk Factors; D000509:alpha-Fetoproteins / Q000032:analysis*
chemical_list: D011933:Reagent Kits, Diagnostic; D000509:alpha-Fetoproteins