Should a woman who is actively miscarrying and presenting with fever, suggesting a potential infected uterus, undergo a transvaginal ultrasound (US) to check for retained products of conception?

Transvaginal Ultrasound in Actively Miscarrying Woman with Fever

Yes, a woman who is actively miscarrying and presents with fever should undergo transvaginal ultrasound to evaluate for retained products of conception (RPOC) and guide appropriate management, as this directly impacts mortality risk from septic complications.

Diagnostic Rationale

Transvaginal ultrasound with Doppler is the cornerstone investigation for suspected RPOC in the setting of fever after pregnancy loss. 1, 2 The presence of fever during active miscarriage raises concern for infected retained tissue (septic abortion/endometritis), which requires urgent identification and treatment to prevent progression to severe sepsis, a life-threatening complication. 2

Key Ultrasound Findings to Identify

• Endometrial mass, focal endometrial thickening, or marked diffuse thickening suggests RPOC, particularly when flow is detected within the endometrial abnormality by Doppler imaging 1
• Vascular echogenic mass is the most specific finding for RPOC, though flow may not be identified in all cases 1
• Thickened endometrial echo complex with variable cutoff of 8-13 mm supports the diagnosis 1
• Superimposed echogenic foci of air within the uterine cavity or hematoma suggests infection 1

Clinical Context and Safety

Transvaginal ultrasound is safe even in the setting of active bleeding and fever. 1 The concern about introducing infection via transvaginal probe is largely theoretical. While there is limited evidence regarding transvaginal ultrasound in premature rupture of membranes (where one randomized trial of 92 patients found no increased chorioamnionitis risk), caution is advised in that specific scenario. 1 However, in active miscarriage with fever, the diagnostic benefit far outweighs theoretical risks, as identifying RPOC is critical for appropriate management. 2

Combined Imaging Approach

• Use both transabdominal and transvaginal approaches for comprehensive evaluation 1
• Transabdominal provides anatomic overview while transvaginal offers superior contrast and spatial resolution 1
• Grayscale and Doppler ultrasound are both essential components of the evaluation 1, 2

Management Algorithm Based on Findings

If RPOC Identified on Ultrasound:

• Initiate broad-spectrum intravenous antibiotics immediately if signs of infection (fever, uterine tenderness, elevated WBC) are present 2
• Proceed with surgical evacuation (manual vacuum aspiration or dilation and curettage) as definitive treatment once RPOC is confirmed with ongoing symptoms 2
• Consider conservative management or uterine artery embolization only if Doppler shows intense myometrial vascularity with peak systolic velocity >83 cm/s, indicating high hemorrhage risk 2

Additional Diagnostic Workup:

• Obtain quantitative serum beta-hCG to assess for persistent or rising levels indicating retained trophoblastic tissue 2
• Complete blood count to evaluate anemia from bleeding and leukocytosis suggesting infection 2
• Pelvic examination to assess cervical dilation, uterine tenderness, and quantify active bleeding 2

Critical Pitfalls to Avoid

Do not delay imaging based on clinical assumptions. 2 Grayscale and Doppler ultrasound are often helpful in distinguishing RPOC from other causes of post-miscarriage bleeding and fever, and early identification directly impacts treatment decisions. 1, 2

Do not rely on single beta-hCG measurement alone. 2 Serial measurements may be needed if initial ultrasound is non-diagnostic, as persistent elevation indicates retained tissue requiring intervention. 2

Do not overlook rare diagnoses. 2 Gestational trophoblastic disease can present similarly to RPOC and requires histopathological confirmation for definitive diagnosis. 1, 2 Complete molar pregnancy can sometimes appear similar to RPOC on ultrasound. 1

Special Considerations

Enhanced myometrial vascularity (EMV) deep to the prior implantation site is commonly confused with arteriovenous fistula or arteriovenous malformation, which may lead to unnecessary workup. 1 True AVMs are rare and usually acquired from previous uterine instrumentation. 1

Fever in the obstetric population has multiple etiologies beyond infection—almost two-thirds of hospitalized obstetric-gynecologic patients with fever may have noninfectious causes. 3 However, in the context of active miscarriage, infection (particularly endometritis with RPOC) must be the primary consideration given the mortality implications. 4, 5