title: Role of second trimester sonography in detecting trisomy 18: a review of 70 cases.
abstract: OBJECTIVE
  To investigate the role of second-trimester sonographic examination in the prenatal diagnosis of trisomy 18.
  
  
  METHODS
  Out of 22,150 fetal chromosomal analyses performed between 1990 and 2004, 70 trisomy 18 fetuses were found. The sonographic findings of this aneuploidy were analyzed.
  
  
  RESULTS
  The average maternal age was 32.4 years; the average gestational age was 19.5 weeks. Major anomalies were seen in 61 (87.1%) of the 70 fetuses with trisomy 18; among these, cardiac anomalies were the most common (47.1%), with a 27.1% incidence of ventricular septal defects. Anomalies of the central nervous system were seen in 35.7% of cases; abnormal head shape was the most frequently detected anomaly in this group (12.9%). Fifty-six (80%) of the fetuses had at least 1 minor anomaly; of these, choroid plexus cyst was the most common (38.6%). Increased nuchal fold thickness was detected in 17.1% of cases.
  
  
  CONCLUSIONS
  The vast majority of trisomy 18 fetuses have sonographically detectable abnormalities in the second trimester. Both the 87.1% frequency of major anomalies and the 80% frequency of minor anomalies are substantially higher than multiple biochemical marker tests could achieve. It was also demonstrated that fetal echocardiography plays a pivotal role in the diagnosis of trisomy 18.
authors.affiliation: Semmelweis Univeristy, Baross u. 27, Budapest 1088, Hungary.
authors.forename: Csaba
authors.initials: C
authors.lastname: Papp
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Ban
authors.forename: Zsanett
authors.initials: Z
authors.lastname: Szigeti
authors.forename: Akos
authors.initials: A
authors.lastname: Csaba
authors.forename: Artur
authors.initials: A
authors.lastname: Beke
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Papp
mesh_terms: D000015:Abnormalities, Multiple / Q000000981:diagnostic imaging* / Q000235:genetics*; D000293:Adolescent; D000328:Adult; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D004452:Echocardiography; D005260:Female; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014314:Trisomy; D016216:Ultrasonography, Prenatal