Objectives: The first aim was to develop a nomogram for the area of the right atrium (ARA) of the fetal heart in uncomplicated singleton pregnancies. The second aim was to assess diagnostic indices of ARA to distinguish between tricuspid regurgitation (TR) with and without concomitant congenital heart defect (CDH).
Methods: The study was conducted between 2014 and 2019. Fetal echocardiography was performed on fetuses with and without TR. For the first aim, ARA was measured in 460 fetuses without proven structural and chromosomal abnormalities, and for the second aim, ARA was measured in 1077 fetuses with TR.
Results: A nomogram for the ARA of fetuses with normal hearts was developed. TR was observed in 4.5% (1077/23,771) of euploid fetuses; 4.3% (1020/23,771) of fetuses had TR without a concomitant CHD, and 0.2% (57/23,771) fetuses had TR with a concomitant CHD. No significant differences in ARAs were found between fetuses with normal hearts without TR (n = 22,694) and fetuses with TR without CHD (n = 1020; p = .751). Fetuses with TR and CHDs had different ARA than fetuses with normal hearts without TR and fetuses with TR without CHD (p < .0005 in both cases).
Conclusions: ARA seems to be an auxiliary marker to distinguish the presence of CHD in fetuses with TR.
Keywords: Area; congenital heart defect; fetus; right atrium; tricuspid regurgitation.