Isolated fetal echogenic intracardiac foci or golf balls: is karyotyping for Down's syndrome indicated?

Objective To determine the prevalence of isolated echogenic intracardiac fo ci and the subsequent risk for Down's syndrome at 18-23 weeks in an unselec ted obstetric population. Design Prospective study. Setting A district general hospital serving a routine obstetric population. Participants 16,917 pregnant women who underwent a routine ultrasound scree ning at 18-23 weeks of gestation between November 1994 and August 1998. Methods All women were offered screening for Down's syndrome by nuchal tran slucency or maternal serum biochemistry. The prevalence of isolated echogen ic intracardiac foci was determined and the relative risk for Down's syndro me was calculated for different ultrasound findings. Results The combined sensitivity of age, nuchal translucency and maternal s erum biochemistry for Down's syndrome was 84% (27/32). The relative risk fo r Down's syndrome was 0.17 (95% CI 0.07-0.41) for the women with normal sca n findings at 18-23 weeks. The prevalence of isolated echogenic intracardia c foci at 18-23 weeks was 0.9% (144/16,917). None of these pregnancies were affected by Down's syndrome. Conclusion The significance of the association between isolated echogenic i ntracardiac foci and Down's syndrome is a matter of ongoing debate. The dat a of this study suggest that in an unselected obstetric population with pri or, effective, routine Down's syndrome screening, the association between i solated echogenic intracardiac foci and Down's syndrome is no longer signif icant.