Post-Miscarriage hCG and Endometrial Findings at 3 Weeks
Yes, these findings are normal and consistent with expected resolution after miscarriage. An hCG of 6 mIU/mL at 3 weeks post-miscarriage, a negative home pregnancy test, and an 8 mm endometrial lining all fall within the expected range for uncomplicated pregnancy loss resolution. 1, 2, 3
Understanding hCG Clearance After Miscarriage
Most standard urine pregnancy tests (sensitivity 20-25 mIU/mL) become negative within 2 weeks after miscarriage, which aligns perfectly with your negative home test at 3 weeks. 2, 3
Serum hCG can persist for several weeks after pregnancy termination, so a low level of 6 mIU/mL at 3 weeks is entirely expected as the hormone clears from your system. 1, 3
The rate of hCG decline after miscarriage follows a predictable pattern: hCG should decrease by at least 21-35% at 2 days and 60-84% at 7 days, depending on the initial level. 4 Your current level of 6 mIU/mL at 3 weeks indicates appropriate clearance.
Endometrial Thickness Interpretation
An 8 mm endometrial lining at 3 weeks post-miscarriage is within normal limits and does not automatically indicate retained products of conception. 1, 3
Retained products of conception typically present with persistent elevation or rising hCG levels, not declining levels like yours. 1, 3 Your declining hCG to 6 mIU/mL argues strongly against this complication.
When to Be Concerned: Red Flags
You should seek immediate medical attention if you develop:
Plateauing or rising hCG levels after this initial decline, which could indicate retained products of conception or, rarely, gestational trophoblastic disease. 3
Heavy vaginal bleeding requiring transfusion, severe pelvic pain, or fever, which may suggest incomplete miscarriage or infection. 5
hCG that fails to reach <5 mIU/mL within 4-6 weeks of the miscarriage, warranting further evaluation. 6, 4
Expected Timeline Going Forward
Your hCG should continue to decline and reach <5 mIU/mL within the next 1-2 weeks (by 4-5 weeks post-miscarriage total). 4, 7
A positive pregnancy test 4 weeks after miscarriage would be abnormal and should prompt evaluation for incomplete abortion or persistent trophoblast. 7
You can be considered "not pregnant" for contraception purposes at ≤7 days after miscarriage, though you are already 3 weeks out. 2, 3
Important Caveat About Molar Pregnancy
If your miscarriage was diagnosed as a molar pregnancy (complete or partial hydatidiform mole), the monitoring requirements are entirely different: you would need hCG checks every 2 weeks until normalization, then monthly monitoring for up to 6 months due to risk of gestational trophoblastic neoplasia. 5, 1, 2, 3
Plateauing or rising hCG after molar pregnancy evacuation is an indication for chemotherapy and requires immediate specialist referral. 5, 3
Bottom Line
Your current findings—hCG of 6 mIU/mL, negative home test, and 8 mm endometrial lining at 3 weeks post-miscarriage—are reassuring and consistent with normal resolution. 1, 2, 3 Continue to monitor for any warning signs listed above, but no immediate intervention is needed based on these results alone.