OBJECTIVE: To investigate the association between fetal nuchal translucency (NT) thickness and neurodevelopmental disorders in euploid children.

METHODS: This study included 222 505 euploid children who had undergone routine first-trimester screening during fetal life. Children were divided according to prenatal NT into three groups: NT < 95(th) percentile (n = 217 103 (97.6%)); NT 95(th) -99(th) percentile (n = 4760 (2.1%)); and NT > 99(th) percentile (n = 642 (0.3%)). All children were followed-up to a mean age of 4.4 years. Information on diagnoses of intellectual disability, autism spectrum disorders (ASD), cerebral palsy, epilepsy and febrile seizures was obtained from national patient registries.

RESULTS: There was no excess risk of neurodevelopmental disorders among euploid children with first-trimester NT 95(th) -99(th) percentile. For children with NT > 99(th) percentile, there were increased risks of intellectual disability (odds ratio (OR), 6.16 (95% CI, 1.51-25.0), 0.31%) and ASD (OR, 2.48 (95% CI, 1.02-5.99), 0.78%) compared with children with NT < 95(th) percentile (incidence of 0.05% for intellectual disability and 0.32% for ASD), however, there was no detected increase in the risk of cerebral palsy (OR, 1.91 (95% CI, 0.61-5.95), 0.47%), epilepsy (OR, 1.51 (95% CI, 0.63-3.66), 0.78%) or febrile seizures (OR, 0.72 (95% CI, 0.44-1.16), 2.65%).

CONCLUSIONS: In a large unselected cohort of euploid children, there was no increased risk of neurodevelopmental disorders among those with a first-trimester NT 95(th) -99(th) percentile. Among euploid children with first-trimester NT > 99(th) percentile, there were increased risks of intellectual disability and ASD, but the absolute risk was reassuringly low (< 1%). Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.