Prevalence and likelihood ratios for aneuploidy in fetuses diagnosed prenatally with isolated congenital cardiac defects

OBJECTIVE: To determine the prevalence and likelihood ratios for aneuploidy in fetuses diagnosed prenatally with isolated congenital cardiac defects. STUDY DESIGN: Retrospective cohort study over a 16-year period using our computerized perinatal database. Cardiac diagnosis was confirmed before establishing karyotype by prenatal diagnosis or postnatal chromosome testing. The screening efficiency and likelihood ratios for any aneuploidy and for trisomy 21, 18, 13, and 45, X were calculated with 95% confidence intervals. RESULTS: A total of 233 (0.4%) isolated congenital cardiac defects were diagnosed among 62,111 patients who had obstetric ultrasounds during the study period. The likelihood ratio (LR+) for any aneuploidy was 24.9 (95% confidence interval [CI], 17.8-35.0). The corresponding likelihood ratio for trisomy 21, 18, and 13 were 29.8 (95% CI, 19.6-45.4), 26 (95% CI, 10.5-64.6), and 19.7 (95% CI, 4.7-82.2), respectively. CONCLUSION: Prenatal diagnosis of congenital cardiac defects is highly associated with aneuploidy.