Color Doppler flow pattern in antenatal diagnosis of unguarded tricuspid valve.

We describe an antenatally diagnosed case of unguarded tricuspid valve in a 15-week fetus. Because of its rarity, the differentiation of this anomaly from other tricuspid valve dysplasias is difficult. Tricuspid regurgitation is the hallmark of Ebstein's anomaly and other tricuspid valve abnormalities, whereas in unguarded tricuspid orifice there is total absence of the valve, resulting in 'to and fro' flow across the right-sided chambers. The color Doppler flow pattern helps in differentiating this anomaly from others. The antenatal diagnosis was confirmed on autopsy.