Do I have retained products of conception with an endometrial thickness of 8 mm, quantitative β‑hCG 6 mIU/mL (negative urine pregnancy test), a clear uterine cavity on ultrasound, and bleeding 3.5 weeks after passing the gestational sac?

You Do Not Have Retained Products of Conception (RPOC)

Based on your clinical presentation—endometrial thickness of 8 mm, β-hCG of 6 mIU/mL (essentially negative), clear uterine cavity on ultrasound, and bleeding 3.5 weeks after passing the gestational sac—you do not have RPOC. This represents a completed early pregnancy loss with normal post-loss bleeding.

Why RPOC is Ruled Out

Your presentation lacks all the diagnostic criteria for RPOC:

• Endometrial thickness <10 mm has a high negative predictive value for incomplete early pregnancy loss, making RPOC highly unlikely in your case 1, 2
• RPOC requires intracavitary tissue with internal vascularity or a persistent gestational sac on ultrasound 1, 2—your ultrasound shows a clear uterine cavity
• Your β-hCG of 6 mIU/mL is essentially at the non-pregnant baseline, inconsistent with retained placental tissue which would maintain elevated hCG levels 3
• The diagnosis of RPOC is supported by vascular flow in the endometrial cavity at color Doppler ultrasound 1, 4—absent in your case

What You Actually Have: Completed Early Pregnancy Loss

Your clinical picture is consistent with a completed early pregnancy loss with normal physiologic bleeding:

• Completed EPL refers to complete passage of the gestational sac and chorionic tissue from the uterus 1
• Bleeding 3.5 weeks after passing the sac can represent normal endometrial shedding or menses resuming, as ovulation can resume within 2-4 weeks post-loss 3
• The clear uterine cavity on ultrasound confirms no retained tissue 1

Enhanced Myometrial Vascularity: A Common Pitfall

If your ultrasound showed increased blood flow in the uterine wall (not the cavity), this is a normal finding:

• Enhanced myometrial vascularity describes typically transient and physiologic focal myometrial vascularity deep to a prior pregnancy implantation site 1, 2
• This occurs following incomplete or completed early pregnancy loss and should not be confused with arteriovenous fistula or arteriovenous malformation 1, 2, 4
• This is a normal post-pregnancy finding, not a complication requiring intervention 2

When to Worry About RPOC

You would need RPOC evaluation if you had:

• Persistent heavy bleeding requiring pad changes every 1-2 hours 3
• Rising or persistently elevated β-hCG levels 2, 3
• Ultrasound showing intracavitary tissue measuring >10 mm with internal blood flow on Doppler 1, 2, 5
• Fever, foul-smelling discharge, or signs of infection 3, 6

What to Expect Now

Your bleeding is likely normal post-loss menses or endometrial shedding:

• Ovulation can resume within 2-4 weeks after early pregnancy loss, so this may be your first period 3
• No further intervention is needed given your negative hCG, thin endometrium, and clear ultrasound 1, 2
• If bleeding becomes heavy (soaking through a pad per hour for 2+ hours) or you develop fever, seek immediate evaluation 3