title: Genetic sonography: a cost-effective method for evaluating women 35 years and older who decline genetic amniocentesis.
abstract: OBJECTIVE
  To determine whether offering genetic sonography to patients who decline invasive testing can increase the detection rate of trisomy 21 and is cost-effective.
  
  
  METHODS
  The detection rate of trisomy 21, the number of pregnancy losses after amniocentesis, and the cost of detecting a single fetus with trisomy 21 were determined in women 35 years and older managed according to the following 3 policies: (1) universal amniocentesis, (2) genetic counseling for maternal age-associated risks for trisomy 21 followed by amniocentesis in patients who elected it, and (3) genetic counseling followed by genetic sonography in patients who originally declined genetic amniocentesis.
  
  
  RESULTS
  From a population of 40,143 women 35 years and older, the expected number of trisomy 21 fetuses was 349. After genetic counseling, 32% of patients declined invasive testing, resulting in detection of 70% of fetuses with trisomy 21. For universal amniocentesis, the cost to detect 1 fetus with trisomy 21 was $138,036. For the 32% who declined invasive testing after genetic counseling and underwent genetic sonography, the cost to detect a single fetus with trisomy 21 was a function of sensitivity and the screen-positive rate. For screen-positive rates between 5% and 25%, genetic sonography resulted in a cost savings between 14.3% and 18.8% when compared with universal invasive testing and resulted in a considerable increase in detection of fetuses with trisomy 21 (77% to 97%).
  
  
  CONCLUSIONS
  A policy of offering genetic sonography followed by amniocentesis to patients 35 years and older who originally decline invasive testing for the diagnosis of trisomy 21 is cost-effective and results in a higher overall detection rate for trisomy 21 without an increased risk of pregnancy loss.
authors.affiliation: Perinatology Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Greggory R
authors.initials: GR
authors.lastname: DeVore
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
mesh_terms: D000328:Adult; D000367:Age Factors; D000649:Amniocentesis / Q000009:adverse effects; D015193:Chorionic Villi Sampling / Q000009:adverse effects; D004314:Down Syndrome / Q000000981:diagnostic imaging / Q000191:economics / Q000235:genetics; D005260:Female; D005817:Genetic Counseling / Q000191:economics*; D006801:Humans; D011247:Pregnancy; D016216:Ultrasonography, Prenatal / Q000191:economics*