After delivery or miscarriage: an echogenic endometrial mass with colour Doppler flow into it is retained products; avascular fluid and clot are not — and a hypervascular myometrial lesion may be an enhanced myometrial vascularity or AVM that must not be curetted blindly.
Orient first
- Endometrial thickness alone is a poor discriminator; vascularity within the mass matters most.
- Clot is avascular and changes on follow-up; retained tissue has feeding vessels from the myometrium.
- Enhanced myometrial vascularity (EMV) after pregnancy usually resolves; high-velocity flow may warrant angiography before intervention.
Acquire the study
- Transvaginal ultrasound with colour and spectral Doppler; transabdominal survey.
The manoeuvre
- Endometrial cavity: echogenic mass vs fluid; thickness in mm in the sagittal plane.
- Colour Doppler: flow within the mass (retained products) vs none (clot).
- Spectral Doppler: peak systolic velocity in the myometrium (report the value in cm/s).
- Myometrium: the interface with the mass; placental site.
What confirms it
- A vascularised echogenic endometrial mass in the clinical setting.
What licenses you to exclude it
- A thin endometrium without a mass or flow makes retained products unlikely.
The classic misread
- Recommending curettage for a hypervascular myometrial lesion without flagging the bleeding risk.