Unusual appearances of echogenic foci within the fetal heart: are they benign?

Nine fetuses with unusually appearing echogenic foci were selected from a series of 65 fetuses with intracardiac echogenic foci studied at the Fetal Diagnosis and Treatment Unit from January 1994 until February 1996. An echogenic focus or foci were defined as a structure or structures within the fetal heart with echogenicity similar to or greater that that of the surrounding bone. Unusually appearing foci were defined as lesions of unusual size, shape, structure or location. Three fetuses had unusually large echogenic foci, and four had multiple foci in both ventricles. In one fetus, two echogenic foci were very close to each other, creating an impression of a 'double' focus within the left ventricle. In another fetus, three echogenic foci were detected. Follow-up protocol for fetuses with echogenic foci included comprehensive ultrasound, amniocentesis and fetal echocardiography. All studied fetuses had normal karyotype. A fetal echocardiogram failed to reveal congenital heart defects. The neonatal outcome was uneventful in seven out of nine cases; one patient decided to terminate her pregnancy for reasons unrelated to the ultrasound findings, and one delivered prematurely at 34 weeks of pregnancy. In conclusion, we failed to find any correlation between unusually appearing echogenic foci and adverse perinatal outcome.