The ultrasonic appearance of intravascular gas in fetal death.

Real-time ultrasonography permits an accurate diagnosis of intrauterine fetal death by documenting absent cardiac motion. Occasionally, intravascular and/or intracardiac gas arises from maceration following fetal demise. The presence of gas in the heart and circulatory system alters the ultrasonic appearance of the fetal body. What may appear to be technically poor visualization of the fetus secondary to tissue maceration, oligohydramnios, or maternal factors may, in fact, be due to reverberation artifacts produced by intravascular gas. These characteristic echogenic foci have been radiographically proven to represent intrafetal gas. Recognition of the appearance of gas in the circulatory system is important since gas is a pathognomonic sign of fetal death.