title: Risk of critical congenital heart defects by nuchal translucency norms.
abstract: OBJECTIVE
  The purpose of this study was to compare the performance of first-trimester nuchal translucency (NT) cutoff of ≥3.5 mm with NT percentiles that were calculated for crown-rump length to identify fetuses with critical congenital heart defects (CCHDs).
  
  
  METHODS
  This was a population-level study of singleton pregnancies in California with NT measurements performed between 11 and 14 weeks of gestation. Eligible cases were those that resulted in live births from 2009-2010 and had information about the presence or absence of CCHDs available in the hospital discharge records through age 1 year (n = 76,089). Logistic binomial regression methods were used to compare the rate of CCHDs by an NT percentile for crown-rump length and millimeter cutpoints.
  
  
  RESULTS
  Compared with fetuses with an NT measurement of <90th percentile, fetuses with an NT of ≥99th percentile were >5 times as likely to have a CCHD (1.3% vs 0.2%; relative risk, 5.66; 95% confidence interval, 3.19-10.04) and fetuses with an NT measurement ≥3.5 mm were >12 times as likely to have a CCHD (2.8% vs 0.2%; relative risk, 12.28; 95% confidence interval, 5.11-29.51). NT ≥99th percentile had a sensitivity of 5.8% and a specificity of 98.9% for the detection of CCHDs compared with 2.6% and 99.8% for NT ≥3.5 mm.
  
  
  CONCLUSIONS
  Results show that NT measurements of ≥99th percentile and ≥3.5 mm are not equivalent and that substantial risk for CCHD extends to the less restrictive ≥99th percentile cutpoint. Data suggest that the use of this cutpoint compared with the current standard could double the number of CCHDs that are identified based on NT risk.
authors.affiliation: Genetic Disease Screening Program, California Department of Public Health, Richmond, CA; Department of Epidemiology and Biostatistics, University of California, San Francisco, School of Medicine, San Francisco, CA. Electronic address: laura.jelliffe@cdph.ca.gov.
authors.forename: Laura L
authors.initials: LL
authors.lastname: Jelliffe-Pawlowski
authors.affiliation: Department of Obstetrics and Gynecology, University of California, San Francisco, School of Medicine, San Francisco, CA.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Norton
authors.affiliation: Department of Pediatrics, Stanford University School of Medicine, Stanford, CA.
authors.forename: Gary M
authors.initials: GM
authors.lastname: Shaw
authors.affiliation: Genetic Disease Screening Program, California Department of Public Health, Richmond, CA.
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Baer
authors.affiliation: Genetic Disease Screening Program, California Department of Public Health, Richmond, CA.
authors.forename: Monica C
authors.initials: MC
authors.lastname: Flessel
authors.affiliation: Genetic Disease Screening Program, California Department of Public Health, Richmond, CA.
authors.forename: Sara
authors.initials: S
authors.lastname: Goldman
authors.affiliation: Genetic Disease Screening Program, California Department of Public Health, Richmond, CA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Currier
mesh_terms: D000328:Adult; D018568:Crown-Rump Length; D005260:Female; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging*; D006801:Humans; D016015:Logistic Models; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012306:Risk; D012680:Sensitivity and Specificity
keywords: critical congenital heart defect; nuchal translucency; prenatal screening