Fetal tricuspid regurgitation at the 11 + 0 to 13 + 6-week scan: association with chromosomal defects and reproducibility of the method.

OBJECTIVE To determine the reproducibility of diagnosing tricuspid regurgitation (TR) at 11 + 0 to 13 + 6 weeks' gestation, to examine further the relationship between TR and the presence of chromosomal defects and to calculate the likelihood ratios for trisomy 21 and trisomy 18 in fetuses with TR. METHODS Pulsed wave Doppler of flow across the tricuspid valve was carried out by 12 obstetricians, trained in fetal echocardiography, to ascertain the presence or absence of TR in 1557 fetuses at 11 + 0 to 13 + 6 weeks. The assessment was carried out immediately before chorionic villus sampling for fetal karyotyping. In 128 cases, assessment of tricuspid flow was also performed by experienced fetal cardiologists to examine the reproducibility of the method. RESULTS Tricuspid flow was successfully assessed in 1538 (98.8%) cases and TR was present in 58 (4.4%) of the 1323 chromosomally normal fetuses, 77 (67.5%) of the 114 cases with trisomy 21, and 14 (33.3%) of the 42 cases with trisomy 18. The kappa coefficient of agreement between obstetricians and cardiologists was 0.872 (P < 0.0001). Logistic regression analysis demonstrated that, in chromosomally normal fetuses, significant prediction of the likelihood of TR was provided by delta nuchal translucency (NT). The likelihood ratio for trisomy 21 and trisomy 18 for TR, derived by dividing the likelihood (%) of TR in trisomy 21 by the likelihood (%) in normal fetuses, decreased with delta NT. CONCLUSION At 11 + 0 to 13 + 6 weeks, TR is a common finding in fetuses with trisomies 21 and 18. Assessment of the tricuspid flow can be performed by sonographers trained in fetal echocardiography.