Elevated first-trimester nuchal translucency increases the risk of congenital heart defects.
OBJECTIVE
We sought to evaluate the association between first trimester nuchal translucency measurement and the risk for major congenital heart defect in chromosomally normal fetuses.


METHODS
First trimester (10 weeks 4 days of gestation to 13 weeks 6 days of gestation) nuchal translucency was obtained in a large prospective multicenter National Institute of Child Health and Human Development study for Down syndrome prediction. The study, which was conducted between May 1998 and December 2000, was restricted to singleton pregnancies. Gestational age was determined by crown rump length measurements. Perinatal outcomes were determined and included the frequency of major congenital heart defect, which was defined as those cases that potentially could require surgery, intensive medical therapy, or prolonged follow-up time. Logistic regression analysis was used to determine whether nuchal translucency was a significant predictor of congenital heart defect.


RESULTS
There were 8167 chromosomally normal pregnancies, of which 21 cases of major congenital heart defect were identified at follow-up examination (incidence, 2.6/1000 pregnancies). The risk of congenital heart defect rose with increasing nuchal translucency measurements. The mean nuchal translucency value for the normal and congenital heart defect groups were 1.5 mm and 1.9 mm, respectively (P = .05). With a nuchal translucency measurement of < 2.0 mm, the incidence of congenital heart defect was 13 of 6757 pregnancies (1.9 of every 1000 pregnancies). At 2.0 to 2.4 mm, the incidence was 5 of 1032 pregnancies (4.8 of every 1000 pregnancies). At 2.5 to 3.4 mm, the incidence was 2 of 335 pregnancies (6.0 of every 1000 pregnancies). At > or = 3.5 mm, the incidence was 1 of 43 pregnancies (23 of every 1000 pregnancies). Logistic regression analysis confirmed that nuchal translucency was associated significantly with congenital heart defect (odds ratio, 2.1; 95% CI, 1.4-3.1; P = .0004).


CONCLUSIONS
Increased first trimester nuchal translucency measurement was associated with a higher risk of major congenital heart defect in chromosomally normal pregnancies. The practical implications of our findings are that patients with unexplained elevations of nuchal translucency may need referral for a fetal echocardiogram.
Bahado-Singh
Ray O
RO
Department of Obstetrics and Gynecology, University of Cincinnati College of Medicine, Ohio 45267-0526, USA. bahadoro@ucmail.uc.edu
Wapner
Ronald
R
Thom
Elizabeth
E
Zachary
Julia
J
Platt
Lawrence
L
Mahoney
Maurice J
MJ
Johnson
Anthony
A
Silver
Richard K
RK
Pergament
Eugene
E
Filkins
Karen
K
Hogge
W Allen
WA
Wilson
R Douglas
RD
Jackson
Laird G
LG
D000328:Adult; D016022:Case-Control Studies; D016001:Confidence Intervals; D005260:Female; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging* / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D048208:Nuchal Translucency Measurement; D016017:Odds Ratio; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011446:Prospective Studies; D018570:Risk Assessment