Comparison of pregnancy outcome of euploid fetuses with increased nuchal translucency (NT) expressed in NT MoM or delta-NT.
OBJECTIVE
To evaluate the outcome of euploid fetuses with increased nuchal translucency thickness (NT) expressed in multiples of the median (MoM) or delta-NT.


METHODS
Included in the study were euploid fetuses with increased NT >or= 95(th) centile, for which information about pregnancy outcome was available. The following parameters were defined as an adverse outcome: miscarriage, structural anomalies justifying termination of pregnancy, and structural anomalies, genetic syndromes and neurodevelopmental problems diagnosed postnatally. Fetal outcome according to NT MoM and delta-NT was calculated using different cut-off values. Calculations of the odds ratio for adverse outcome were performed using either NT MoM or delta-NT as a predictor in logistic regression models.


RESULTS
The study comprised 168 euploid fetuses. Of these, 38 (23%) had an adverse outcome: 11 (6%) had miscarriages, 14 (8%) were terminated because of fetal abnormalities detected on the prenatal scan and 13 (7%) were found postnatally to have abnormalities. The incidence of cases exhibiting an adverse outcome was 5.3%, 19.2% and 58.5% for NT values of 1.6-1.9, 2.0-3.0 and >3.0 MoM, respectively (P < 0.0001, chi(2) test), and 3.9%, 16.7% and 62.8% for delta-NT values of 1.0-1.4, 1.5-2.5 and >2.5 mm, respectively (P < 0.0001, chi(2) test). Using cut-offs of 2.0 MoM and delta-NT of 1.5 mm, the odds ratios for adverse outcome were 10.2 (95% CI, 3.4-30.4) and 15.4 (95% CI, 4.2-43.6), respectively.


CONCLUSIONS
Both the NT MoM and delta-NT approaches may be used to determine cases which require additional antenatal investigation as well as fetal karyotyping. For this purpose we suggest using a cut-off of either 2.0 MoM or a delta-NT of 1.5 mm.
Maymon
R
R
Department of Obstetrics and Gynecology, Assaf Harofe Medical Center, affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Israel. intposgr@post.tau.ac.il
Tercanli
S
S
Dreazen
E
E
Sartorius
G
G
Holzgreve
W
W
Herman
A
A
D000022:Abortion, Spontaneous; D000032:Abortion, Therapeutic; D000782:Aneuploidy; D016009:Chi-Square Distribution; D000013:Congenital Abnormalities / Q000000981:diagnostic imaging; D005260:Female; D005315:Fetal Diseases / Q000000981:diagnostic imaging* / Q000235:genetics*; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D011247:Pregnancy; D011256:Pregnancy Outcome; D012016:Reference Values; D012044:Regression Analysis; D016216:Ultrasonography, Prenatal