Threatened miscarriage and intrauterine hematomas. Sonographic and biochemical studies.

In a prospective study of 406 women with threatened miscarriage (TMC), 22 (5.4%) had an intrauterine hematoma (less than 16 mL) noted ultrasonically, decreasing in size as the patients experienced repeated episodes of bleeding. Twenty (91%) of the hematomas visualized were subchorionic and two (9%) were retroplacental. None of these women subsequently miscarried. Human chorionic gonadotrophin (hCG), Schwangerschafts protein 1 (SP1), and pregnancy-associated plasma protein A (PAPP-A) levels measured in these patients were not significantly different in women with or without hematomas. We conclude that the presence of small intrauterine hematomas in women with TMC does not increase the risk of miscarriage.