OBJECTIVE: To describe the distribution of the fetal nuchal translucency thickness (NT) according to type of chromosomal aberration in a large unselected population. METHODS: Data on pregnancies with an NT measurement performed at gestational age 11+3 - 13+6 weeks from 2008-2011 were retrieved from the Danish National Fetal Medicine Database. Information on any genetic analysis for aneuploidy performed pre- or postnatally was also obtained. The abnormal results were grouped into 14 types of @entity2008 . Distributions of NT measurements were summarized by aberration and compared with the normal/no karyotype group. RESULTS: 215,223 singleton pregnancies were included in the cohort. 10,548 had a normal karyotype and 1,286 had an aberration. Plots of the NT measurements showed that like trisomy 21,18, and 13 and @entity2689 , the distribution for the unbalanced translocations was shifted towards larger NTs. The distributions for the balanced translocations, the uncommon @entity3769 and the @entity8338 more closely resembled that of the normal/no karyotype population. CONCLUSION: Fetuses with aneuploidies have NT distributions visually different from normal fetuses, with the exception of @entity8338 and uncommon autosomal @entity3769 . The distributions differ in shape according to type of @entity2008 .

Nuchal translucency distributions for different XXXX in a large unselected population cohort.

@entity2008 :: ('MESH:D002869', 'Disease') :: ['chromosomal anomalies', 'chromosomal anomaly'] @entity2689 :: ('MESH:D014424', 'Disease') :: ['monosomy X'] @entity8338 :: ('MESH:D057885', 'Disease') :: ['triploidies'] @entity3769 :: ('MESH:D014314', 'Disease') :: ['trisomies']
@entity2008 :: (MESH:D002869,Disease) :: ['chromosomal anomalies']
