How should secondary postpartum hemorrhage (bleeding 24 hours to 6 weeks after delivery) be evaluated and managed?

Secondary Postpartum Hemorrhage: Evaluation and Management

Begin with transvaginal ultrasound with color Doppler as your first-line imaging, then treat the underlying cause—retained products of conception require surgical curettage, vascular abnormalities need arterial embolization, and infection demands antibiotics plus source control. 1, 2

Initial Diagnostic Approach

Transvaginal ultrasound with color Doppler is the imaging modality of choice for evaluating secondary PPH (bleeding occurring 24 hours to 6 weeks postpartum). 3, 1 This modality identifies the two most common culprits:

• Retained products of conception (RPOC) appear as a vascular echogenic mass with intralesional flow on color Doppler—the most specific sonographic finding. 1
• An endometrial echo complex >8–13 mm suggests RPOC, though this overlaps with normal postpartum appearance. 1
• Endometritis is the other leading cause, particularly after cesarean delivery (RPOC predominates after vaginal delivery: 32.8% vs. 10.8%). 1

Critical imaging pitfall: Do not rely solely on ultrasound to exclude pseudoaneurysm—serpiginous myometrial vessels on Doppler raise suspicion but require CT angiography or formal angiography for confirmation. 1

When to Escalate Imaging

Reserve contrast-enhanced CT or multiphasic CT angiography for hemodynamically stable patients when: 3, 1

• Ultrasound is inconclusive
• You need to localize active bleeding (CTA achieves ~97% accuracy for contrast extravasation) 1
• You suspect complications like ovarian vein thrombosis, infected hematomas >5 cm, or uterine artery pseudoaneurysm 1, 2

Cause-Specific Treatment Algorithm

For Retained Products of Conception

• Surgical curettage is the definitive treatment—not antibiotics alone. 2
• Medical management (when attempted) shows only 8.2–84.6% resolution rates in recent studies, compared to 89.3–100% for surgical approaches. 4
• One retrospective study suggested medical management may preserve future fertility better than surgery, but this remains controversial and should not delay definitive treatment when bleeding is significant. 5

For Vascular Abnormalities (Pseudoaneurysm, Vessel Subinvolution)

• Arterial embolization is the preferred intervention, with success rates up to 95–100%. 2, 4, 6
• Vessel subinvolution of the placental bed—a rare cause—presents with recurrent bleeding and requires histological confirmation showing dilated "clustered" myometrial arteries with thrombi. 7

For Infection (Endometritis)

• Antibiotics treat the infectious component but do not stop the hemorrhage itself—this is a critical distinction. 2
• If bleeding persists despite antibiotics, you must identify and address the mechanical source (RPOC, hematoma requiring drainage). 1, 2
• Re-dose antibiotic prophylaxis if blood loss exceeds 1,500 mL regardless of initial cause. 2

Common Clinical Pitfalls

Do not wait for laboratory confirmation before acting: 1

• If blood loss exceeds 1,500 mL, initiate massive transfusion protocol immediately while addressing the underlying cause
• Coagulopathy develops in 17% of cases with >2,000 mL blood loss 1

Recognize normal vs. abnormal postpartum findings: 8

• Endometrial debris and gas are present in 20–25% of normal postpartum women
• Endometrial thickness up to 2–2.5 cm can be normal in the first 6 weeks
• Bleeding that suddenly increases in volume or continues beyond 6 weeks warrants evaluation 8

Avoid misdiagnosing rare causes: 1

• Gestational trophoblastic disease (choriocarcinoma) appears as a hypervascular intrauterine mass—check β-HCG when clinical picture doesn't fit
• Uterine scar dehiscence after cesarean can be difficult to differentiate from normal scar on imaging 1

Management Outcomes by Modality

Based on systematic review data from the past 30 years: 4

• Medical management alone: 71.9–73.7% resolution
• Surgical management: 89.3–92.0% resolution
• Transcatheter arterial embolization: 87.5–100% resolution

The evidence base remains limited—all available studies are small, retrospective, and carry serious risk of bias, but the pattern clearly favors interventional approaches (surgical or radiological) over medical management alone when bleeding is significant. 4