Distinction between subchorionic hematoma and unfused amnion in patient with vaginal bleeding at 13 weeks' gestational age

Transabdominal sagittal sonogram of uterus reveals subchorionic hematoma (H) extending posteriorly around chorion (arrows) and lifting edge of anterior placenta (P). Appearance should not be confused with that of unfused amnion. Amnion is the thin membrane continuous along anterior placental edge, but limited by umbilical cord insertion; subchorionic bleeding leads to edge of placenta.