What is the most likely diagnosis and appropriate management for a female in her mid-twenties, with a history of incomplete miscarriage at 9 weeks gestation, who underwent manual vacuum aspiration (MVA) and was discharged on analgesics and doxycycline (doxycycline), now presenting with recurrent low abdominal pain and vaginal bleeding one week post-procedure?

Most Likely Diagnosis and Management

The most likely diagnosis is retained products of conception (RPOC), potentially complicated by endometritis, given the recurrent pain and bleeding one week post-manual vacuum aspiration. 1, 2

Differential Diagnosis

The clinical presentation of recurrent lower abdominal pain and vaginal bleeding one week after MVA for incomplete miscarriage points to several key possibilities:

• Retained products of conception (RPOC) - This is the primary concern, as continued bleeding or persistent symptoms after evacuation strongly suggest incomplete removal of pregnancy tissue 1, 2
• Endometritis with or without RPOC - The patient was discharged on doxycycline, suggesting prophylaxis was given, but infection can still develop, particularly if tissue remains 1
• Uterine perforation (less likely given initial symptom resolution) - Would typically present with more acute severe symptoms 3, 4, 5
• Gestational trophoblastic disease - Should be considered if hCG levels remain inappropriately elevated, though less common 1

Immediate Investigations Required

Primary Diagnostic Workup

• Transvaginal ultrasound with Doppler imaging - This is the cornerstone investigation. Look specifically for endometrial mass, focal endometrial thickening, or marked diffuse thickening suggestive of RPOC, particularly when flow is detected within the endometrial abnormality by Doppler 1, 2

• Quantitative serum beta-hCG level - Essential to assess for persistent or rising levels, which would indicate retained trophoblastic tissue or, rarely, gestational trophoblastic disease 1, 6

• Complete blood count - To assess for anemia from ongoing bleeding and evaluate for leukocytosis suggesting infection 6

• Pelvic examination - Assess for cervical dilation, uterine tenderness (suggesting endometritis), and quantify active bleeding 7

Additional Considerations

• Blood cultures if febrile - To identify sepsis if endometritis is suspected 1
• Endometrial thickness measurement - An endometrial thickness <8 mm makes RPOC less likely, while marked thickening (>25 mm) is highly suggestive 1

Treatment Algorithm

If RPOC Confirmed on Ultrasound

Repeat surgical evacuation (MVA or dilation and curettage) is the definitive treatment when RPOC is identified with ongoing symptoms 1, 2. The ACR guidelines indicate that once RPOC is diagnosed, tailored intervention such as curettage is appropriate 1

• Surgical evacuation has a 95-96% success rate for complete evacuation 3, 5
• MVA under paracervical block can be performed as an outpatient procedure 3, 4
• Medical management with misoprostol is an alternative but has slightly lower complete evacuation rates (96% vs 98% for surgery) and higher rates of unplanned procedures 8

If Endometritis Suspected

• Broad-spectrum intravenous antibiotics if signs of infection (fever, uterine tenderness, elevated white blood cell count) 1
• Common regimens include clindamycin plus gentamicin, or second-generation cephalosporins
• Continue until afebrile for 24-48 hours, then transition to oral antibiotics

If Vascular Uterine Anomalies Identified

• Conservative management or uterine artery embolization if Doppler shows areas of intense myometrial vascularity with peak systolic velocity >83 cm/s, which increases risk of significant hemorrhage 1
• Most myometrial vascular anomalies will resolve with removal of RPOC or expectant management 1

Critical Pitfalls to Avoid

• Do not assume successful evacuation based solely on initial symptom resolution - Up to 2-5% of MVA procedures result in incomplete evacuation requiring repeat intervention 3, 4, 5

• Do not delay imaging - Grayscale and Doppler ultrasound are often helpful in distinguishing RPOC from other causes of post-procedure bleeding 1, 2

• Do not rely on single beta-hCG measurement - Serial measurements may be needed if initial ultrasound is non-diagnostic, as persistent elevation indicates retained tissue 1, 6

• Do not overlook rare diagnoses - While uncommon, gestational trophoblastic disease can present similarly and requires histopathological confirmation 1

Expected Outcomes

With appropriate repeat evacuation for RPOC, complete resolution occurs in >95% of cases 3, 5. If endometritis is present and treated promptly with antibiotics, outcomes remain excellent with minimal risk of long-term complications such as Asherman's syndrome, particularly when suction methods rather than sharp curettage are used 5, 8.