Sonographic spectrum of retroplacental hemorrhage.

Retroplacental hemorrhage (RPH), or abruptio placentae, usually occurs in the third trimester of pregnancy and may or may not be clinically significant. Sonographic criteria necessary for diagnosis of RPH include visualization of a linear or biconcave, and usually well-marginated mixed echogenic or anechoic region posterior to the placenta. Large areas of hemorrhage may cause bulging of the chorionic plate while small areas may be difficult to discern with routine scanning. Secondary signs of RPH include associated intraplacental anechoic regions secondary to bleeding or infarction and visualization of intra-amniotic hemorrhage. In this report, nine cases of pathologically confirmed RPH are reviewed. Also reviewed are normal and other pathological conditions of the placenta which may mimic RPH but should not be confused with the sonographic diagnosis.