How should a woman presenting with delayed (secondary) postpartum bleeding (≥24 hours to 6 weeks after delivery) be evaluated and managed?

Evaluation and Management of Delayed Postpartum Hemorrhage

A woman presenting with delayed postpartum bleeding (≥24 hours to 6 weeks after delivery) should undergo immediate transvaginal ultrasound with Doppler imaging and serial quantitative β-hCG testing, as this combination is the diagnostic cornerstone for identifying retained products of conception and other vascular causes. 1

Initial Clinical Assessment

Perform a focused pelvic examination to assess:

• Cervical dilation with active bleeding 1
• Uterine tenderness suggesting endometritis 1
• Quantification of ongoing blood loss (>1 pad per hour for ≥2 continuous hours requires urgent intervention) 1

Obtain immediate laboratory work:

• Serial quantitative β-hCG levels (persistent or rising values indicate retained trophoblastic tissue) 1
• Complete blood count to evaluate anemia and leukocytosis 1

Differential Diagnosis by Delivery Type

After vaginal delivery, the most common causes are:

• Retained products of conception (32.8% of cases) 2
• Subinvolution of the placental bed 1, 2

After cesarean delivery, the most common causes are:

• Endometritis (more frequent than after vaginal delivery) 1, 2
• Retained products of conception (10.8% of cases) 2
• Infected bladder flap, subfascial, or perivaginal hematomas 2
• Uterine scar dehiscence 2

First-Line Imaging: Transvaginal Ultrasound with Doppler

Diagnostic ultrasound criteria for RPOC:

• Echogenic endometrial mass with Doppler-detected vascularity is the most specific finding 1
• Focal endometrial thickening with blood flow 1
• A discrete, identifiable mass rather than diffuse thickening 1

Critical interpretation pitfalls to avoid:

• Endometrial thickness alone should NOT be used to diagnose RPOC; thickness up to 20-25 mm in the early postpartum period is nonspecific 1
• An 8 mm endometrial stripe is normal postpartum healing 1
• Debris and occasional gas are present in 20-25% of normal postpartum women 1
• Absence of Doppler vascularity does NOT rule out RPOC, as avascular retained tissue can occur 1

Advanced Imaging When Ultrasound Is Inconclusive

MRI is the superior modality for:

• Detecting RPOC as a variably enhancing intracavitary mass 3, 1
• Identifying myometrial defects with intact serosal layer (uterine dehiscence) 3, 1
• Revealing associated complications such as abscess or ovarian vein thrombosis 3, 1

CT or CTA should be reserved for hemodynamically unstable patients:

• Multiphasic CT achieves 97% accuracy for detecting active contrast extravasation 3, 1
• CTA localizes feeding arteries of pseudoaneurysms and arteriovenous malformations for treatment planning 3, 1
• Active extravasation is visualized in 41-74% of secondary PPH cases on CTA 3, 2

Important CT limitations:

• RPOC can be difficult to distinguish from postpartum blood products, even on multiphase studies 3, 1
• False positives occur when dilated, tortuous hypertrophic uterine arteries mimic extravasation 3, 2
• False negatives occur in atony due to slow intermittent hemorrhage 3, 2

Red Flags for Gestational Trophoblastic Disease

Suspect GTD when β-hCG shows:

• Plateau over 3-4 consecutive weekly measurements 1
• Rise >10% across three values within 2 weeks 1
• Persistence of detectable hCG for ≥6 months after pregnancy loss 1
• Initial hCG >100,000 mIU/mL 1

On imaging, GTD appears as a heterogeneous hypervascular intrauterine mass, indistinguishable from RPOC unless invasive or metastatic disease is present. 3, 1

Treatment Algorithm

Immediate Surgical Intervention Indicated For:

• Heavy bleeding requiring transfusion 1
• Doppler-confirmed vascular RPOC 1
• Persistent or rising β-hCG levels 1

Repeat surgical evacuation (manual vacuum aspiration or dilation and curettage) is the definitive therapy when RPOC is confirmed and the patient remains symptomatic. 1

Uterine Artery Embolization Indicated For:

• Doppler ultrasound showing intense myometrial vascularity with peak systolic velocity >83 cm/s (indicating heightened hemorrhage risk) 1
• Vascular anomalies such as pseudoaneurysm or arteriovenous malformations 1, 4
• Success rates up to 95% have been reported 4

Infection Management:

Administer broad-spectrum intravenous antibiotics when signs of infection are present:

• Fever ≥38°C (100.4°F) 1
• Uterine tenderness 1
• Elevated white blood cell count 1
• Foul-smelling discharge 1

Follow-Up Monitoring

Serial β-hCG measurements must demonstrate progressive decline to undetectable levels to confirm resolution of trophoblastic tissue. 1

Re-evaluate if:

• Vaginal bleeding persists beyond 6 weeks 1, 5
• Bleeding suddenly increases in volume 1, 5