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HCG Level After Miscarriage: When Does It Come Back To Zero?

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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 can increase after a miscarriage in the case of:

  1. Heterotropic pregnancy: Simultaneous occurence of extra-uterine (ectopic pregnancy) and intrauterine pregnancy)
  2. Persistent trophoblastic disease: Molar tissue starts growing again after the removal of molar pregnancy

How Soon Can You Get Pregnant After A Miscarriage?

While some doctors may recommend waiting for three months several experts opine that there is no need to delay pregnancy after an early pregnancy loss (4).

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 (5).

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 (6).

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.

References:

1. HCG (Urine); University of Rochester Medical Center
2. Danielle Betz and Kathleen Fane; Human Chorionic Gonadotropin (HCG); : StatPearls Publishing; (2020)
3. Pregnancy Test (hCG); American Association for Clinical Chemistry
4. Karen C. Schliep, et al.; Trying to Conceive After an Early Pregnancy Loss: An Assessment on How Long Couples Should Wait; Obstet Gynecol (2017).
5. 1st Trimester Bleeding and Pregnancy Loss; OB-GYN 101: Introductory Obstetrics & Gynecology
6. 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).