What is hCG? (hCG Hormone & Pregnancy Guide for Women)

If you have recently conceived or are trying to conceive (TTC), you’ve probably already heard of the notorious “pregnancy hormone” hCG. It’s not only responsible for helping a pregnancy progress and sustain itself, it’s also the primary hormone that is tested in order to confirm a pregnancy in the first place. 

To learn more about this critical hormone, here’s a closer look at what hCG is, what it does in the body, and what you can expect your hCG levels to be before and after pregnancy. We’ll also cover how to test for hCG, and what you should do if your hCG levels are abnormal.  

Please note that men also have small traces of hCG in the body. However, this article will focus specifically on hCG and its role in pregnancy. 

What is hCG?

Human chorionic gonadotropin (hCG) is a type of hormone found in both men and women. In men and non-pregnant women, hCG is produced in small amounts in the pituitary gland, liver, and colon. In pregnant women, however, the growing placenta begins production of hCG at the time of implantation. 

HCG is famously known as the “pregnancy hormone” because of the vital role it plays in early pregnancy. It is also the hormone that is detected by pregnancy tests to confirm pregnancy. 

What does hCG do?

The primary function of hCG is to encourage the corpus luteum to produce progesterone, which helps to support the growth of the uterus and uterine lining. It also helps to prevent contractions that may inhibit this growth. By supporting the growth and health of the uterus, an embryo is able to develop in a safe environment. 

Without hCG, progesterone would not be able to be produced at high enough levels to sustain a pregnancy. 

hCG and your body

Pre-pregnancy

In non-pregnant women, hCG can still be found in small amounts that would go undetected with a pregnancy test. 

What’s happening in your body

HCG can still be found in small amounts in the body, and it is known to be produced in the pituitary gland, liver, and colon. However, it is not critical to any specific bodily function. 

Normal levels

HCG levels before pregnancy are typically less than 5 mIU/ml. If hCG levels are consistently elevated above 5 mIU/ml, this may be an indicator of certain cancers such as ovarian cancer, breast cancer, lung cancer, or kidney cancer. 

Pregnancy

From the moment implantation occurs, hCG levels should rise rapidly. On average, hCG is detectable with a pregnancy test as early as 8 days after conception. 

What’s happening in your body

At the time of implantation, the growing placenta begins to produce hCG – which in turn helps the corpus luteum produce progesterone. HCG levels then rise rapidly, doubling in concentration every one to two days for the first four weeks of pregnancy. 

Around the sixth week, it can take three to four days for hCG to double and by week 10, hCG levels reach their peak before leveling off and remaining constant until delivery. 

Normal levels

HCG levels can vary greatly among pregnancies. However, The American Pregnancy Association estimates that “normal” levels typically lie within the following ranges: 

• Week 3: 5-50 mIU/ml
• Week 4: 5-426 mIU/ml
• Week 5: 18-7,340 mIU/ml
• Week 6: 1,080-56,500 mIU/ml
• Weeks 7-8: 7,650-229,000 mIU/ml
• Weeks 9-12: 25,700-288,000 mIU/ml
• Weeks 13-16: 13,300-254,000 mIU/ml
• Weeks 17-24: 4,060-165,400 mIU/ml
• Weeks 25-40: 3,640-117,000 mIU/ml

If your hCG levels fall outside of these ranges, your doctor may want to run further tests to assess the health of your pregnancy. 

For example, in cases where hCG levels are low or slow to rise, this could be a sign of a blighted ovum, ectopic pregnancy, or impending miscarriage. Alternatively, it may be a sign that you have simply miscalculated your conception date or have taken the test incorrectly.

In cases where hCG levels are higher than normal, this may indicate that you are having twins or multiples. In rare cases, high levels of hCG may also be a sign of a molar pregnancy or Down’s syndrome. 

To ease any concerns you may have about the health of your pregnancy, try to relax and speak with your doctor. They will be able to better assess your situation. 

Post-Pregnancy

After delivery, hCG levels will begin to fall back to their pre-pregnancy levels of  5 mIU/ml. This process can take up to six weeks post-pregnancy. 

What’s happening in your body

Once a baby is born, your body halts the production of hCG because it no longer needs to sustain a pregnancy. In addition to hCG, estrogen and progesterone levels will drop as well. It’s important to note that these postpartum hormonal fluctuations can lead to mood swings, feelings of sadness or anxiety, and in some cases a diagnosis of perinatal depression. 

If you find that you are struggling with your postpartum mental health for two weeks or more, know that you are not alone! An estimated one in five women experience perinatal depression, so it’s okay to reach out to your doctor for further support and treatment. 

Normal levels

Immediately after delivery, you can expect hCG levels to drop with a half-life of 24 to 36 hours until they return back to their baseline of less than .05mIU/ml.

Miscarriage

After a miscarriage, hCG levels will fall back to their pre-pregnancy levels. This may take up to six weeks depending on how far along the pregnancy is. 

After delivery, hCG levels will begin to fall back to their pre-pregnancy levels of less than .05 mIU/ml. This process can take up to six weeks post-pregnancy. 

What’s happening in your body

In the event of a miscarriage, the body stops producing hCG. Without hCG, estrogen and progesterone levels will also fall. Again, this hormonal fluctuation may cause emotional side effects such as fatigue, sadness, anxiety, and difficulties with sleep. Due to the traumatic nature of miscarriage, it’s a good idea to reach out to your doctor, a counselor, or a local support group if you are struggling to cope with your mental health after a miscarriage. 

Normal levels

After a miscarriage, hCG levels will drop with a half-life of 24 to 36 hours until reaching their baseline of less than .05 mIU/ml. The amount of time that this takes will depend on how far along you are in your pregnancy. 

Immediately after delivery, you can expect hCG levels to drop with a half-life of 24 to 36 hours until they return back to their baseline of less than .05mIU/ml.

Monitoring hCG

It is common for doctors to monitor hCG levels in early pregnancy, especially in patients who have recently experienced a miscarriage. 

How to test your hCG levels

The only way that you can receive your exact hCG concentration level is by having your blood tested at your doctor’s office. This type of test is often referred to as a “beta hCG test”, and it will require a blood sample to be taken and analyzed at a laboratory. 

Through regular testing, your doctor can determine whether or not your hCG levels are where they should be.  

To make hCG testing more convenient and cost-effective, Mira plans to release hCG wands in the future. Please check our shop regularly for further details and to stay in the loop. 

What are normal levels?

On average, hCG levels fall within the following ranges:

• Week 3: 5-50 mIU/ml
• Week 4: 5-426 mIU/ml
• Week 5: 18-7,340 mIU/ml
• Week 6: 1,080-56,500 mIU/ml
• Weeks 7-8: 7,650-229,000 mIU/ml
• Weeks 9-12: 25,700-288,000 mIU/ml
• Weeks 13-16: 13,300-254,000 mIU/ml
• Weeks 17-24: 4,060-165,400 mIU/ml
• Weeks 25-40: 3,640-117,000 mIU/ml

Estimates provided by The American Pregnancy Association. 

What should you do if you have abnormal levels?

If your hCG levels are above or below the “normal” threshold, do not panic. HCG levels can vary greatly among pregnancies and it may not be a cause for concern. Instead, speak with your doctor about your concerns and they will run further testing if needed. 

hCG FAQs