What investigations should be done for post Medical Termination of Pregnancy (MTP) bleeding?

Investigations for Post-MTP Bleeding

Transvaginal ultrasound (TVS) should be the first-line imaging modality for investigating post-MTP bleeding, with particular attention to detecting retained products of conception and vascular abnormalities. 1

Primary Diagnostic Approach

Transvaginal Ultrasound

• Most important initial investigation due to its accessibility, safety, and ability to visualize the uterine cavity
• Key findings to look for:
  • Echogenic endometrial mass with vascularity (most diagnostic combination for retained products of conception) 2
  • Thickened endometrial echo complex (EEC) >10mm 3
  • Presence of vascularity on color or power Doppler (increases positive predictive value for RPOC) 4
  • Vascular abnormalities such as arteriovenous malformations or pseudoaneurysms

Laboratory Tests

• Complete blood count to assess hemoglobin levels and degree of blood loss
• Coagulation profile (PT, aPTT, fibrinogen) especially if heavy bleeding is present
• Serum β-hCG levels to rule out persistent trophoblastic tissue or gestational trophoblastic disease 2
  • Important: Ensure the hCG assay can detect all forms of beta hCG equally well, as cancer-related beta hCG can exist in several different forms/fragments 2

Timing of Investigations

• Initial ultrasound evaluation should be performed at presentation with bleeding
• If ultrasound findings are suspicious for retained products of conception at 2 weeks post-MTP, consider repeating the ultrasound 4-6 weeks later (6-8 weeks post-MTP) before diagnosing failure of the procedure 5
• This is because ultrasound findings suspicious for retained products at 2 weeks post-MTP do not conclusively indicate failure of the procedure 5

Advanced Imaging (When Initial Evaluation is Inconclusive)

CT with IV Contrast

• Indicated when:
  • Ultrasound findings are equivocal
  • Suspicion of active hemorrhage requiring localization
  • Need to identify hematomas or other complications
• Helps determine presence of active ongoing hemorrhage, localize bleeding, and identify the source 2
• Can detect vascular complications such as bladder flap hematoma, subfascial hematoma, or perivaginal space hematoma 2

CT Angiography (CTA)

• Indicated for persistent hemorrhage after empiric treatment 2
• Excellent accuracy (97%) for detection of active extravasation 2
• Can identify serpiginous myometrial vessels and prominent parametrial vessels (signs of vascular uterine anomalies) 2

MRI Pelvis

• Consider when ultrasound findings are equivocal but patient is hemodynamically stable
• Better than CT for distinguishing retained products from blood clots 1
• Can identify associated findings such as abscess or infected hematoma 2

Diagnostic Pitfalls to Avoid

1. Normal postpartum findings can be misinterpreted as abnormal:

   • Debris and gas are common in up to 25% of early postpartum cases 1
   • Thickened endometrial echo complex up to 2-2.5 cm can be normal in early postpartum period 2

2. False negatives in RPOC detection:

   • Absence of vascularity on Doppler does not exclude RPOC, which can be avascular 1

3. Misdiagnosis of vascular lesions:

   • Highly vascular RPOC can be mistaken for uterine arteriovenous malformation 4
   • CTA can be falsely positive due to dilated tortuous hypertrophic uterine arteries mimicking extravasation 2

4. Age consideration:

   • Older women are more likely to have ultrasound findings suspicious for retained products of conception 5

Monitoring for Complications

• Monitor for signs of cardiovascular complications, which although rare, can include infective endocarditis, takotsubo cardiomyopathy, arrhythmias, and spontaneous coronary artery dissection 6
• Follow-up should include monitoring for infection, with appropriate cultures if endometritis is suspected

By following this systematic approach to investigating post-MTP bleeding, clinicians can accurately diagnose the cause and implement appropriate management strategies to reduce morbidity and improve outcomes.