Objective: To test the hypothesis that increased first trimester nuchal translucency is associated with isolated cardiac foci in the second trimester.
Methods: We identified all pregnancies delivered between January 1997 and June 2000. We included 7686 normal singleton fetuses who had a nuchal translucency scan and either a subsequent normal anomaly scan at 18-23 weeks' gestation (n = 7447) or isolated cardiac foci (n = 239). Fetuses were divided into two groups: normal (95th percentile or less) and increased (greater than 95th percentile) nuchal translucency.
Results: The prevalence of cardiac echogenic foci in fetuses with normal nuchal translucency was 218 of 7427 (2.9%; 95% confidence interval [CI] 2.6, 3.3%), whereas 21 of 259 fetuses (8.1%; 95% CI 5.1, 12.1%) with increased nuchal translucency were subsequently found to have cardiac foci. The adjusted odds ratio for cardiac echogenic foci in cases of increased nuchal translucency was 2.92 (95% CI 1.83, 4.66).
Conclusion: An association exists between first trimester nuchal translucency and second trimester cardiac echogenic foci. Risk calculation algorithms for trisomy 21 based on nuchal translucency thickness should not use cardiac foci as an independent marker.