Diagnosis:
The classic symptoms and signs of abruptio placentae are vaginal bleeding, abdominal pain, uterine contractions, and uterine tenderness. The clinician must be aware that all of these are not invariably present and that the absence of one or more does not exclude the diagnosis or necessarily suggest a mild form. Ultrasonography is an important tool in the diagnosis of third-trimester bleeding. Its chief role is the diagnosis of placenta previa. The role of an ultrasonogram in the diagnosis of abruption is more problematic. The finding of a retroplacental sonolucency is consistent with retro-placental blood and is highly suggestive of placental abruption. However, a normal ultrasonogram of the placenta does not preclude the diagnosis of placental abruption. The sensitivity of ultrasonography has been reported as approximately 25%. Newer modalities under investigation include Doppler flow changes and thrombomodulin -- a marker of endothelial cell damage (8). Currently, however, placental abruption remains a clinical diagnosis. Heavy vaginal bleeding in a woman with hypertension, regular contractions, and no evidence of placenta previa render placental abruption the most likely diagnosis. The other diagnoses may be associated with vaginal bleeding, but they do not fit the clinical picture. Bleeding from vasa previa, if heavy, would produce fetal heart rate changes and would occur after the membranes had ruptured. Although bleeding from placenta accreta or succenturiate lobe may occur before delivery, such bleeding usually occurs in the third stage of labor.