A 32-year-old multiparous woman is evaluated for postpartum hemorrhage on postpartum day 3. She had a normal vaginal delivery 3 days ago with an estimated blood loss of 400 mL. Now she presents with heavy vaginal bleeding, passage of clots, and a tender, enlarged uterus. Hemoglobin has dropped from 11 g/dL to 8.5 g/dL. On ultrasound, there is echogenic material within the uterine cavity. What is the most common cause of late postpartum hemorrhage in this case?

Explanation

## Most Common Cause of Late Postpartum Hemorrhage **Key Point:** Retained products of conception (RPOC) is the most common identifiable cause of late postpartum hemorrhage (PPH occurring >24 hours to 12 weeks postpartum), and the clinical + ultrasound findings in this vignette are classic for RPOC. ### Definition and Pathophysiology Retained products of conception occur when placental tissue or membranes remain within the uterine cavity after delivery. This leads to: 1. Failure of the uterus to contract adequately (atony at the placental site) 2. Persistent bleeding from the placental bed 3. Possible secondary infection (endometritis) 4. Ultrasound evidence of echogenic material within the uterine cavity ### Why RPOC — Not Subinvolution — Fits This Vignette | Feature | This Patient | RPOC | Subinvolution | |---------|-------------|------|---------------| | **Onset** | Day 3 postpartum | 1–4 weeks PP | 1–6 weeks PP | | **Bleeding** | Heavy with clots | Heavy with clots | Heavy, prolonged | | **Uterine size** | Enlarged, tender | Enlarged, boggy | Larger than expected | | **Fever** | Not mentioned | Absent (unless infected) | Absent | | **Ultrasound** | Echogenic material in cavity | Echogenic debris/mass | Thickened endometrium, dilated vessels | **The ultrasound finding of echogenic material within the uterine cavity is the hallmark of RPOC**, not subinvolution. Subinvolution classically shows a thickened endometrium with dilated spiral vessels on Doppler, without a discrete echogenic mass. ### Clinical Pearl Per **Williams Obstetrics (26th ed., Ch. 41)**, retained placental fragments are the most common cause of late PPH requiring surgical intervention. The combination of: - Heavy bleeding with clots - Enlarged, tender uterus - Echogenic intrauterine material on ultrasound …constitutes the classic triad of RPOC until proven otherwise. ### Distinguishing RPOC from Subinvolution - **RPOC:** Discrete echogenic mass or debris on ultrasound; responds to uterine evacuation (suction curettage) - **Subinvolution:** Diffuse thickening of endometrium with patent spiral arteries on Doppler; responds to uterotonics (oxytocin, ergot alkaloids) ### Management of RPOC 1. **Confirm diagnosis:** Ultrasound (echogenic material >10 mm in cavity); color Doppler to assess vascularity 2. **Surgical evacuation:** Suction curettage is definitive treatment 3. **Uterotonics:** Adjunct to reduce bleeding during/after evacuation 4. **Antibiotics:** If signs of concurrent endometritis 5. **Supportive care:** Iron supplementation; transfusion if Hb <7 g/dL **High-Yield:** In any patient with late PPH and echogenic intrauterine material on ultrasound, RPOC is the diagnosis to establish first. Subinvolution is a diagnosis of exclusion made when no retained tissue is identified. [cite: Williams Obstetrics 26e Ch 41; Cunningham et al., Late Postpartum Hemorrhage]