hCG (human chorionic gonadotrophin) is a pregnancy hormone that your placenta produces to support fetal growth. In healthy pregnancies, it usually doubles every 48 to 72 hours in the first few weeks, and could be detected through blood and urine tests (1). If the hCG levels fall, it could be an indication of a miscarriage, medically referred to as a non-viable pregnancy.
Read this MomJunction post to understand how long the hCG levels remain after a miscarriage, and when they generally fall to the pre-pregnancy state.
How Long Does It Take For The hCG Levels To Fall To Zero After A Miscarriage?
The duration varies from woman to woman. It is likely to depend on how high your hCG levels were during the miscarriage. Usually, test results of fewer than five mIU/mL are considered negative or zero (1).
If you had a miscarriage early in your pregnancy, your levels are usually low, and hCG levels return to zero in less time. On the other hand, if the levels are high at the time of the miscarriage or if you had a miscarriage late in your pregnancy, it might take several days or weeks to return to zero (2).
According to the American Association for Clinical Chemistry (AACC), urine hCG and serum hCG levels may take anywhere between nine and 35 days to disappear from your system (3).
Why Do hCG Levels Keep Increasing After A Miscarriage?
The hCG level readings may show an increase following a miscarriage due to the following reasons:
- Pituitary disorders in the case of premenopausal and menopausal women (4)
- Gestational trophoblastic diseases (a group of tumors) that may develop in the womb could increase the hCG levels (5)
- Phantom hCG, wherein antibodies in the blood may interfere with the hCG test results and show a higher level of hCG (5)
- Germ cell tumors (immature reproductive cells) and cancers occurring in the ovaries
- Cancers of the liver, breast, skin, stomach, and lung
- Non-cancerous conditions such as inflammatory bowel diseases, cirrhosis, and duodenal ulcers (6)
How Soon Can You Get Pregnant After A Miscarriage?
The standard recommendation by most doctors is to wait at least three months to try to get pregnant after a miscarriage. The World Health Organization (WHO) recommends waiting period of six months for the body to heal and the cycles to get back to normal. However, there might need further research (7).
Can You Get A Pregnancy False-Positive Reading After Miscarriage?
Yes, you might get a false-positive test reading after a miscarriage because hCG may still remain in your bloodstream for weeks following a pregnancy loss. Thus, the test readings might show that you are pregnant even when you are not (8).
Can You Ovulate With hCG In Your System After A Miscarriage?
hCG hormone is likely to suppress your normal ovulation process. Your next cycle may start only when the hCG levels drop below 5mIU/mL (9).
It is likely to be normal for the pregnancy test to show positive following a miscarriage. It takes time for you to cope with the loss, but you will soon get back to normal. If you have concerns about hCG levels after a miscarriage, talk to your doctor. They can guide you on when to have your next pregnancy and the care you need to take.
2. Danielle Betz and Kathleen Fane; Human Chorionic Gonadotropin (HCG); : StatPearls Publishing; (2020)
3. Pregnancy Test (hCG); American Association for Clinical Chemistry
4. Bashir A. Laway and Shahnaz A. Mir; Pregnancy and pituitary disorders: Challenges in diagnosis and management; Indian J Endocrinol Metab (2013).
5. Jennifer Goldstein, et al.; A non-pregnant woman with elevated beta-HCG: A case of para-neoplastic syndrome in ovarian cancer; Gynecol Oncol Rep. (2016).
6. hCG Tumor Marker; American Association for Clinical Chemistry
7. Karen C. Schliep, et al.; Trying to Conceive After an Early Pregnancy Loss: An Assessment on How Long Couples Should Wait; Obstet Gynecol (2017).
8. 1st Trimester Bleeding and Pregnancy Loss; OB-GYN 101: Introductory Obstetrics & Gynecology
9. Beata E. Seeber; What serial hCG can tell you, and cannot tell you, about an early pregnancy; Fertility and Sterility; American Society for Reproductive Medicine – Elsevier Inc (2012).