title: Prenatal diagnosis of chromosomal abnormalities in a resource-poor setting.
abstract: OBJECTIVE
  To compare the efficacy and efficiency of systematic, ultrasound-based risk adjustment using a published algorithm with that of a maternal age cutoff of 37 years for the prenatal detection of chromosomal abnormalities (especially autosomal trisomies).
  
  
  METHODS
  These approaches were compared in a retrospective study of 136 chromosomal abnormalities confirmed by karyotyping prenatally (n=46) or postnatally (n=90). There were 114 autosomal trisomies.
  
  
  RESULTS
  Maternal age was known for 103 fetuses with confirmed abnormalities. The ultrasound-based risk adjustment approach was more sensitive for autosomal trisomy (93.9% vs 44.1%), and karyotyping for younger women with abnormalities on ultrasound was more effective than routine karyotyping in older women (1 trisomy detected in 13.5 vs 42.8 samples, P<0.001). A lack of screening was the main reason for the postnatal diagnosis.
  
  
  CONCLUSIONS
  Ultrasound-based risk adjustment was the more effective approach.
authors: Department of Obstetrics and Gynecology, Tygerberg Hospital, University of Stellenbosch, Cape Town, South Africa. lgeerts@sun.ac.za
authors: Lut
authors: L
authors: Geerts
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000465:Algorithms; D025063:Chromosome Disorders / Q000175:diagnosis*; D005260:Female; D006297:Health Services Accessibility; D006801:Humans; D007621:Karyotyping; D008875:Middle Aged; D011247:Pregnancy; D012189:Retrospective Studies; D020379:Risk Adjustment; D012680:Sensitivity and Specificity; D014314:Trisomy / Q000175:diagnosis*; D016216:Ultrasonography, Prenatal / Q000379:methods / Q000592:standards*; D055815:Young Adult