(Abstracted from J Ultrasound Med 2018;37:1725–1732)
A common finding on early first-trimester ultrasound (US) examinations, subchorionic hematoma (SCH) occurs in both asymptomatic patients and those presenting with vaginal bleeding. Previous studies assessing the risk of first-trimester pregnancy failure when an SCH is seen on an early pregnancy sonogram have used a variety of grading systems for characterizing the size of the hematoma, including subjective grading of the SCH as small, moderate, or large; calculating the volume of the SCH from its US measurements; estimation of hematoma size as a fraction of gestational sac size; and estimated fraction of the gestational sac that is surrounded by hematoma.
Departments of Radiology (H.T.H., E.A.A., S.M.D., R.P.G., H.E.P., P.M.D., C.B.B.) and Obstetrics and Gynecology (E.S.G.), Brigham and Women's Hospital, Harvard Medical School, Boston, MA