Increased nuchal translucency and pregnancy outcome: a retrospective study of 1063 consecutive singleton pregnancies in a single referral institution

• Published in: Prenatal diagnosis 2013-09, Vol.33 (9), p.856-862
• Main Authors: Äyräs, Outi, Tikkanen, Minna, Eronen, Marianne, Paavonen, Jorma, Stefanovic, Vedran
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Crown-Rump Length; Down syndrome; False Positive Reactions; Female; Fetal Diseases - diagnostic imaging; Fetal Diseases - epidemiology; Fetal Diseases - genetics; Fetuses; Humans; Infant, Newborn; Karyotyping; Middle Aged; Nuchal Translucency Measurement - statistics & numerical data; Pregnancy; Pregnancy Outcome - epidemiology; Referral and Consultation - statistics & numerical data; Retrospective Studies; Ultrasonic imaging; Young Adult
• ISSN: 0197-3851; 1097-0223
• DOI: 10.1002/pd.4143

ABSTRACT Objectives The goals of this study are to assess pregnancy outcome with increased nuchal translucency (NT) and to determine the risk of adverse pregnancy outcome in relation to the degree of increased NT. Methods All singleton pregnancies with increased NT at the first screening ultrasound examination referred to the Department of Fetal Medicine at the Helsinki University Central Hospital during 2002 to 2007 were included. Pregnancy outcomes and short‐term outcomes of the newborns were recorded and analyzed. Results Of the 1063 pregnancies, karyotype was normal in 834 (78%). The majority, 611 (73%), of euploid fetuses was in the lowest NT group (95th percentile – 3.4 mm). Percentage of favorable outcome decreased from 92% in the lowest NT group (95th percentile – 3.4 mm) to 18% in the highest NT group (≥6.5 mm). Structural defects or genetic disorders were observed in 74 (9%) of cases with normal karyotype, of which 43 (58%) resulted in live birth, 25 (34%) in termination of pregnancy, and 6 (8%) in miscarriage or perinatal death. Conclusions Even minimal (95th percentile – 3.4 mm) increase in NT thickness is associated with adverse pregnancy outcome also in euploid fetuses. © 2013 John Wiley & Sons, Ltd. What is already known about this topic? Increased nuchal translucency is associated with chromosomal defects, structural defects, and genetic syndromes. The thicker the nuchal translucency, the worse the prognosis for pregnancy; this applies also to fetuses with normal karyotype. What does this study add? Even minimally increased nuchal translucency thickness (95th percentile – 3.4 mm) is associated with adverse pregnancy outcome. However, in euploid pregnancies with normal second trimester ultrasound, favorable outcome occurs in 97% of cases. This study contains a large number of fetuses, and the obtained results are of essential importance for parental counseling.