Influence of maternal BMI on genetic sonography in the FaSTER trial

Kjersti M. Aagaard-Tillery, T. Flint Porter, Fergal D. Malone, David A. Nyberg, Jamie Collins, Christine H. Comstock, Gary Hankins, Keith Eddleman, Lorraine Dugoff, Honor M. Wolfe, Mary E. D'Alton

Research output: Contribution to journalArticlepeer-review

95 Scopus citations


Objective: We sought to evaluate the influence of maternal body mass index (BMI) on sonographic detection employing data from the FaSTER trial. Method: Unselected singleton pregnancies underwent detailed genetic sonogram to evaluate for structural fetal anomalies and soft markers for aneuploidy. BMI (kg/m 2) were calculated from reported initial visit values. Sensitivity, specificity, false positive and false negative rates (FPR and FNR), likelihood ratio, detection rates, and a missed diagnosis rate (MDR: FNR + marker recorded as 'missing'/N) were calculated. Results: Eight thousand five hundred and fifty-five patients with complete BMI information had detailed genetic sonography. A lower sensitivity with an elevated FNR and MDR was observed in obese women for multiple aneuploid markers (e.g. ≥2 markers 32% sensitivity with 68% FNR among BMI <25 vs 22% and 78% among BMI >30). Similarly, the detection rate for cardiac anomalies among women at BMI <25 was higher (21.6%) at a significantly lower FPR (78.4%; 95% CI 77.3-79.5%) in comparison to obese women (8.3% with FPR 91.7%; 95% CI 90.1-93.2%). In a logistic regression model, maternal obesity significantly decreased the likelihood of sonographic detection of common anomalies (adjusted OR 0.7; 95% CI 0.6-0.9; p = 0.001). Conclusion: The performance of second trimester genetic sonography is influenced by obesity, with a significantly higher MDR for multiple minor markers and lower likelihood for detecting common anomalies.

Original languageEnglish (US)
Pages (from-to)14-22
Number of pages9
JournalPrenatal Diagnosis
Issue number1
StatePublished - Jan 2010


  • Detection of fetal aneuploidy
  • Fetal Down syndrome markers
  • Fetal genetic sonogram
  • Nuchal translucency
  • Obesity
  • Prenatal sonography
  • Trisomy 21 detection

ASJC Scopus subject areas

  • Obstetrics and Gynecology
  • Genetics(clinical)


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