Mild tricuspid regurgitation: A benign fetal finding at various stages of pregnancy

Objective: Tricuspid regurgitation (TR) may accompany various anatomical malformations and/or dysfunction of the fetal right heart. It may also appear in an anatomically healthy heart. With improved ultrasound modalities, more cases than the previously estimated prevalence of fetal TR in the low-risk population are being diagnosed. The objective of this study was to determine the prevalence of mild fetal TR in a low-risk obstetric population. Methods: In 157 low-risk pregnant women (age range, 18-42 years) undergoing both early second-trimester and mid-trimester targeted organ scanning, including complete fetal echocardiography according to the five transverse planes technique, the apical four-chamber view was visualized using gray-scale, color Doppler and spatiotemporal image correlation (STIC) ultrasound modalities, with optimal acquisition parameters. Results: Mild-to-moderate TR was discovered in the early second-trimester scan in 131/157 (83.4%) fetuses. No cases of cardiac malformation were found. All fetuses showed normal flow in the ductus venosus, including in one case diagnosed with moderate TR. Only in 39 (24.8%) cases was mild TR still evident at the second, mid-trimester scan. Neonatal echocardiography revealed mild TR in eight (5.1%) cases. No cases of chromosomal anomalies were detected. Conclusion: Mild TR is a benign finding of a temporal nature in early pregnancy.