The Outcome of Fetuses with Increased Nuchal Translucency at the First Trimester Chromosomal Anomaly Screening

  • Derya Eroglu
  • Hilal Karahan Beyhan
  • Mesut Öktem
  • Esra Kusçu
  • Filiz Yanik

Turk J Obstet Gynecol 2005;2(4):337-341

OBJECTIVE: To evaluate the outcome of fetuses diagnosed to have increased nuchal translucency at the first trimester chromosomal anomaly screening. Design: Retrospective evaluation of the outcomes of fetuses with increased nuchal translucency among the cases undergoing first trimester chromosomal anomaly screening at the Department of Obstetrics and Gynecology, Baskent University, Ankara, between January 2004 and September 2005. Setting: Department of Obstetrics and Gynecology, Baskent University School of Medicine, Ankara Patients: Fetal nuchal translucency measurements were performed in a total of 452 pregnancies as a part of first trimester chromosomal anomaly screening. Seven cases with nuchal translucency measurements above the 95th percentile according to the fetal crown-rump length were considered for evaluation. Main outcome measures: Fetal mortality and morbidity RESULTS: Increased nuchal translucency was observed in 1.3% (7/452) of the cases undergoing first trimester chromosomal anomaly screening. Two of the three fetuses with nuchal translucency of 2.5 to 3 mm had structural anomalies (one had bilateral congenital diaphragmatic hernia and the other had unilateral complet cleft lip and palate), and these pregnancies ended up with live births at term. The third case ended up with fetal intrauterine exitus owing to osteogenesis imperfecta type II. The infant with bilateral congenital diaphragmatic hernia died at the seventh hour of age due to pulmonary hypoplasia. Trisomy 18 (n=2), trisomy 21 (n=1), and Turner’s syndrome (n=1) were the diagnoses in the fetuses with fetal nuchal translucency measurements of ≥6 mm, and all of these cases resulted in termination of the pregnancies. CONCLUSION: Increased nuchal translucency is a typical sonographic sign for trisomy 21 and other chromosomal abnormalities. It is also associated with fetal and neonatal death, a wide range of fetal malformations, skeletal dysplasias, and genetic syndromes. The prevalence of chromosomal defects and major fetal anomalies increase in parallel with the increase in the nuchal translucency thickness.

Keywords: fetal chromosomal anomalies, fetal sonography, nuchal translucency, prenatal diagnosis, structural fetal anomalies