What is hCG?

What is hCG? 
 

HCG stands for human chorionic gonadotropin, which is a hormone produced by the placenta during pregnancy. It’s a common biomarker used to detect pregnancy either through a blood or urine test.

HCG’s main role is the stimulation of progesterone – a hormone that helps in maintaining and supporting a healthy pregnancy. In addition to its role in pregnancy, it can also sometimes be used in IVF, or to monitor certain types of cancer.
 

What's a normal level of hCG?
 

The normal level of hCG in a non-pregnant woman is usually less than 5mIU/mL. However, during pregnancy, the level of hCG increases. In the first few weeks of pregnancy, the average hCG level roughly doubles every two to three days. And then levels gradually drop off as the pregnancy progresses.

The table below shows the approximate hCG ranges according to gestation [1].

It is important to note that levels can vary depending on the individual and the measurement of hCG levels alone may not provide enough information to diagnose or monitor the progress of pregnancy. Every individual is different, and these figures are given as a guide only. hCG can be a good indicator of pregnancy and pregnancy progression, but other tests such as ultrasounds should be used alongside. Top of Form
 

What causes a raised hCG?  
 

Pregnancy is the most common cause of raised hCG (as the placenta releases hCG). In some cases, a high hCG level could be due to a molar pregnancy (but this is very rare).

A molar pregnancy is when there’s a problem with a fertilised egg, which means a baby and a placenta do not develop in the way they should [2]. This can cause very high levels of hCG. A molar pregnancy isn’t usually picked up until the 12-week ultrasound.

There are also other reasons your hCG levels may be higher than expected in pregnancy, such as a multiple pregnancy. If you are expecting twins or more, your hCG levels may naturally be higher than in people who are only carrying one baby.
 

What causes raised hCG levels when not pregnant?
 

In other rarer cases, raised hCG levels can indicate something other than pregnancy.

Causes for elevated hCG levels that aren’t due to pregnancy include:

• Medications – certain medications such as those used in infertility treatments like IVF. These medications often contain hCG and therefore can provide a false representation of the amount of natural hCG in your blood.
• Cancer – some cancers, such as testicular or ovarian cancer, can produce high levels of hCG [3]. If you have elevated hCG levels but are not pregnant, further tests may be needed to identify the underlying cause.
• False positive – as with most tests, a false positive is possible. False positives for hCG are usually down to medications, some medical conditions, or sample errors.
   

What causes abnormally low hCG levels during pregnancy?
 

HCG levels tend to increase as the pregnancy progresses, then gradually decline in the later stages. In some cases, low hCG levels may indicate an issue with the pregnancy, though this is not always the case.

Factors that may cause abnormally low hCG levels include:

1. Ectopic pregnancy – an ectopic pregnancy is where a fertilised egg implants outside of the uterus, usually in the fallopian tubes. This can result in lower-than-expected hCG levels. Ectopic pregnancies cannot progress because they can lead to a rupture of tubes. You can find support and more information about ectopic pregnancies on The Ectopic Pregnancy Trust website.
2. Blighted ovum – also known as anembryonic pregnancy, a blighted ovum describes when the cells of a baby stop developing early on, and the tiny embryo is reabsorbed into the sac that continues to grow. This is a rare cause of lower-than-expected hCG levels in pregnancy. You can find more information and support on the Miscarriage Association website.

If your midwife or doctor suspects an issue with pregnancy due to abnormally low hCG levels, they may recommend further testing such as an ultrasound scan or additional blood tests.
 

Does a low hCG level in early pregnancy indicate miscarriage?
 

Sometimes low hCG levels may indicate a miscarriage. But in most cases, it’s more likely that the dates of your pregnancy have been miscalculated. If you are concerned about miscarriage, speak to your midwife or GP. You can also find support on Tommy’s website.
 

How can I measure my levels of hCG at home?
 

You can measure your levels of hCG with either an at-home urine test or with an at-home blood test. Our Pregnancy Blood Test can be taken from the comfort of your own home. We’ll send you everything you need, including a pre-paid return envelope for your sample.
 

How early can hCG be detected in pregnancy?
 

HCG can be detected in either blood or urine tests as early as ten days after conception.

However, it is important to note that hCG levels increase rapidly, and at different rates depending on the individual, so if taken too early, a pregnancy test may produce a false negative result. For the most accurate results, it is recommended to wait until the day after your period is due.

Is a urine or blood test more accurate for testing hCG?
 

Both urine and blood tests can be accurate for testing hCG but it will depend on the sensitivity of the test and how early you are taking it.

Generally, urine pregnancy tests can detect hCG levels at a concentration of 20-25mIU/mL (five to six weeks pregnant). And blood tests may be able to detect from as little as 5mIU/mL. Therefore, sometimes a blood test may be able to detect pregnancy earlier than urine tests.

Blood tests can also be useful in monitoring the progress of a pregnancy test or in detecting potential issues.
 

Can I raise my hCG levels during early pregnancy?

In short, no. A person cannot raise their hCG levels naturally as it is produced by the placenta. However, there are certain things you can do to give your baby the best start, such as taking folate supplements and taking up healthier lifestyle habits, such as quitting smoking.

Your midwife or GP can give you more information on how to look after you and your baby in the early stages, including a list of foods you should be wary of.

Where can I get support if I’m worried about my hCG levels?
 

If you are worried about your hCG levels, you can speak to your GP or midwife. There are many causes of unexpected hCG levels in pregnancy. While many of these are no cause for concern, it’s important to let your healthcare professional know

In the meantime, if you are pregnant and would like more information and support on early pregnancy, you can visit:

• Tommy’s
• Bounty
• NHS

References

1. Beta hCG (no date) com. Available at: https://perinatology.com/calculators/betahCG.htm (Accessed: April 18, 2023).
2. Molar pregnancy (no date) NHS choices. NHS. Available at: https://www.nhs.uk/conditions/molar-pregnancy/#:~:text=A%20molar%20pregnancy%20is%20when,support%20available%20to%20help%20you. (Accessed: April 18, 2023).
3. Mustafa, A. et al. (2016) “An unexpected reason for elevated human chorionic gonadotropin in a young woman cervical squamous carcinoma,” Saudi Medical Journal, 37(8), pp. 905–907. Available at: https://doi.org/10.15537/smj.2016.8.14529