Understanding HCG Levels in Pregnancy and Miscarriage

Understanding HCG Levels in Pregnancy and Miscarriage
Published : Jun 13, 2024

Human chorionic gonadotropin (hCG) is a well-known pregnancy hormone. It is a hormone that is detected during at-home pregnancy tests and one of the hormones your doctor might decide to monitor with blood work if you have a history of miscarriage or pregnancy loss. 

In early pregnancy, its main function is to ramp up the body’s production of estrogen and progesterone. This further aids in supporting the growth of the uterus and uterine lining. 

Until 6 to 10 weeks of pregnancy, hCG increases rapidly and might double every two days. If hCG fails to get doubled during this time of your pregnancy, it can be a sign that your pregnancy is at risk. 

What is human chorionic gonadotropin (hCG)? 

Human chorionic gonadotropin (hCG) is a hormone that is produced only during pregnancy as it is produced by the placenta. In the first trimester of pregnancy, levels of hCG rise and can be detected in your urine within a day or two of the implantation. 

Does low levels of hCG mean a miscarriage? 

Not necessary. The main symptoms that doctors use to diagnose a potential miscarriage are:

  • Spotting and bleeding
  • Abdominal and back pain
  • Loss of pregnancy symptoms
  • Fluid or tissue which passes from the vagina

However, if you have low hCG levels during the first trimester, you might be at an increased risk of miscarriage. If this is the case, your doctor can conduct some tests to know the health of your pregnancy. 

What is miscarriage? 

A miscarriage is the loss of a developing fetus in the first 20 weeks of pregnancy. However, most miscarriages happen in the first three months. 

Some common symptoms of miscarriage include:

  • Loss of mucus or clot-like tissue from the vagina
  • Spotting or bleeding
  • Abdominal or back pain or cramp

If you experience any of these symptoms, contact your doctor because miscarriage can lead to severe complications.

HCG levels in pregnancy

If you think you are pregnant, a doctor will first take a blood sample from a vein to check the hCG levels. However, if there is no hCG present in your blood, this does not mean you are not pregnant. It might be possible that you are too early in your pregnancy for hCG levels to increase.

When hCG levels are higher than 5 million international units per milliliter, it usually indicates pregnancy. The result of the first test is contemplated as a baseline level. This level can range from small amounts to larger amounts.

The baseline level is necessary due to a concept that doctors call doubling time. During the first four weeks of your pregnancy, hCG levels will double every two to three days. After the sixth week, they will start to double almost every 96 hours. 

However, if your baseline level is more than five mIU/mL, the doctor can repeat the test to see if the number doubles.

HCG levels during a miscarriage

During a miscarriage, your body stops producing hCG. This results in hCG levels falling nonstop until they come to their pre-pregnancy baseline, which takes time of almost six weeks. 

During a miscarriage, the exact hCG levels to expect entirely depends on how high hCG levels were before the pregnancy loss. In case the loss occurred early in the pregnancy, then hCG levels can take only a few days to reset. 

Causes of low hCG levels

When a woman develops an ectopic or intrauterine pregnancy, there might be low or inadequate increasing hCG levels. You need to know that low hCG levels are not a cause but a symptom of such conditions. 

When considering hCG levels and pregnancy, doctors usually consider two factors: the initial hCG level and how fast it increases during the pregnancy. 

Therefore, levels of hCG usually double every 48 hours in almost 99% of viable pregnancies within the first several weeks of your pregnancy. 

Is it possible to get pregnant with low hCG levels?

hCG levels are different in every woman, so just because your numbers are on the low side does not mean you will not have a healthy pregnancy. The important thing is that your levels should trend upwards overall. 

On the other hand, one lower-than-expected hCG reading is not a sign of a problem. However, hCG levels that trend downward continuously in the first trimester can show an unpractical pregnancy.

If your hCG levels are rising, it is a sign that your pregnancy is progressing as it should. 


hCG levels can differ among pregnant women and from pregnancy to pregnancy. In case you have already experienced low hCG and miscarriage, there is still a chance to conceive again and give birth to a healthy baby. Consult your doctor if you have any concerns about hCG levels and miscarriage.