Increased nuchal translucency in chromosomally normal fetuses and pregnancy outcomes – a retrospective study

Abstract

Objectives: The objective was to study the outcomes of fetuses with increased nuchal translucency ≥3.5 mm and normal karyotype. Materials and methods: We performed a retrospective study on pregnancy outcomes and children development in 87 women with increased fetal nuchal translucency and normal karyotype who underwent chorionic villus sampling at our department. Mean observation period was 12 months after birth. Adverse pregnancy outcome was defined as miscarriage and intrauterine fetal demise, termination of pregnancy, structural defect, neonatal death, genetic syndrome and other major abnormalities. Results: The total incidence of adverse pregnancy outcome was 39.1% (n=34). The likelihood of an adverse pregnancy outcome, a major structural defect or major heart defect increased significantly with nuchal translucency (OR 3.77). 68 children (78.2%) were born alive. Nuchal translucency was significantly higher in newborns with adverse pregnancy outcome than in healthy children [4.1 mm vs. 5.7 mm; p<0.01]. After a normal anomaly scan at 20 weeks gestation the risk of adverse outcome was 14.5% (n=9, 9/62) and increased with nuchal translucency thickness from 10.2% for NT 3.5 – 4.4 mm to 100% for NT ≥6.5 mm [p<0.01]. There was no significant relationship of fetal gender, maternal age and persistence of the nuchal fold with adverse pregnancy outcome. The rate of neurodevelopmental delay was 3.4 % and was not higher than in the general population. Conclusions: The overall risk of adverse pregnancy outcome was around 40% and was related to nuchal translucency thickness. After excluding structural defects, the chance of a favorable outcome was 85%. The rate of neurodevelopmental delay in fetuses with increased nuchal translucency, normal karyotype and normal anatomy is not higher than in the general population.