Using fetal nuchal translucency to screen for major congenital cardiac defects at 10-14 weeks of gestation: population based cohort study

Objectives To examine the utility of measuring fetal nuchal translucency th ickness in screening for major defects of the heart and great arteries at 1 0-14 week of gestation. Design Population based cohort study. Subjects 29 154 singleton pregnancies with chromosomally normal fetuses at 10-14 weeks of gestation. Setting Fetal medicine centre in London. Main outcome measure Prevalence of major defects of the heart and great art eries. Results Of 50 cases with major defects of the heart and great arteries (pre valence 1.7 pet 1000 pregnancies) 28 (56%, 95% confidence interval 42% to 7 0%) were in the subgroup of 1822 pregnancies with fetal nuchal translucency thicknesses above the 95th centile of the normal range. The positive and n egative predictive values for this cut off point of nuchal translucency thi ckness were 1.5% and 99.9% respectively. Conclusions Measurement of fetal nuchal translucency thickness-traditionall y used to identify fetuses at high risk of aneuploidy-at 10-14 weeks of ges tation can identify a large proportion of fetuses with major defects of the heart and great arteries.