OBJECTIVES: To systematically review and, when feasible, pool, published data regarding the prevalence of childhood neurodevelopmental delay in fetuses with increased first-trimester nuchal translucency (NT), normal karyotype and absence of structural defects or identifiable syndromes.METHODS: MEDLINE and SCOPUS searches using combinations of the terms 'nuchal translucency' AND 'outcome*' were complemented by perusal of the references of the retrieved articles and an additional automated search using the 'search for related articles' PubMed function. Only children with a normal karyotype and no structural defects or syndromic abnormalities were included in the analysis. Between-studies heterogeneity was assessed using the I(2) statistic.RESULTS: The total prevalence of developmental delay in all 17 studies was 28/2458 (1.14%; 95% CI, 0.79-1.64; I(2) = 57.6%). Eight studies (n = 1567) used NT > 99(th) centile as the cut-off; 15 children (0.96%; 95% CI, 0.58-1.58%) were reported as having developmental delay (I(2) = 72.2%). Four studies (n = 669) used the 95(th) centile as the cut-off for increased NT; seven children (1.05%; 95% CI, 0.51-4.88%) were reported as having developmental delay (I(2) = 29.2%). Five studies used 3.0 mm as the cut-off for increased NT; the pooled rate of developmental delay was six of 222 children (2.70%; 95% CI, 1.24-5.77%; I(2) = 0.0%).CONCLUSION: The rate of neurodevelopmental delay in children with increased fetal NT, a normal karyotype, normal anatomy and no identifiable genetic syndromes does not appear to be higher than that reported for the general population. More large-scale, prospective case-control studies would be needed to enhance the robustness of the results.