Nuchal translucency distributions for different chromosomal anomalies in a large unselected population cohort.
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 to 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 chromosomal anomalies. Distributions of NT measurements were summarized by aberration and compared with the normal/no karyotype group.


RESULTS
A total of 215 223 singleton pregnancies were included in the cohort; 10548 had a normal karyotype and 1286 had an aberration. Plots of the NT measurements showed that like trisomy 21, 18 and 13 and monosomy X, the distribution for the unbalanced translocations was shifted towards larger NTs. The distributions for the balanced translocations, the uncommon trisomies and the triploidies more closely resembled that of the normal/no karyotype population.


CONCLUSIONS
Fetuses with aneuploidies have NT distributions visually different from normal fetuses, with the exception of triploidies and uncommon autosomal trisomies. The distributions differ in shape according to type of chromosomal anomaly. © 2015 John Wiley & Sons, Ltd.
Fetal Medicine Unit, Department of Obstetrics and Gynecology, Aarhus University Hospital, Aarhus, Denmark.
Marianne
M
Christiansen
Center for Fetal Medicine, Department of Obstetrics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
Charlotte K
CK
Ekelund
Fetal Medicine Unit, Department of Obstetrics and Gynecology, Aarhus University Hospital, Aarhus, Denmark.
Olav Bjørn
OB
Petersen
Department of High Risk Obstetrics, Royal Prince Alfred Hospital, Sydney, Australia.
Jon
J
Hyett
Centre for Biostatistics, Bioinformatics and Biomarkers, Plymouth University, Plymouth, United Kingdom.
Nathan
N
Eastwood
NIHR CLAHRC South West Peninsula (PenCLAHRC), University of Exeter Medical School, Exeter, United Kingdom.
Susan
S
Ball
Center for Fetal Medicine, Department of Obstetrics, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
Ann
A
Tabor
Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark.
Ida
I
Vogel
D000782:Aneuploidy; D025063:Chromosome Disorders / Q000000981:diagnostic imaging* / Q000235:genetics; D016208:Databases, Factual; D003718:Denmark; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012189:Retrospective Studies