Everything You Need to Know About HCG Testing

If you are looking to become pregnant, you may be becoming familiar with HCG test strips. But how do HCG test strips work, and how important is HCG during my pregnancy?

Human Chorionic Gonadotropin (HCG) might sound like something out of a sci-fi movie, but it’s actually an important hormone that can be used as a marker of early pregnancy. Here is everything you need to know about HCG levels and pregnancy:


What Is HCG?


HCG is a hormone produced by the cells surrounding the forming embryo. Its primary function is to prevent the corpus luteum (the incredibly helpful, but also temporary, gland that produces progesterone during ovulation) from disappearing. Progesterone levels need to remain high to allow the fertilized egg to implant into the uterus wall for pregnancy to occur. HCG is also associated with the formation of the placenta.

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What are HCG Test Strips?

HCG test strips, more commonly known as pregnancy tests, are a modern at-home option to test for pregnancy. HCG is excreted from the body through the urine – that’s why you have to pee on a stick to get pregnancy test results! Typically, it is recommended to take an HCG test after at least 1-3 days after missing your regular period. 


The HCG Level Chart


The HCG levels chart was created to help provide normal ranges for HCG levels at weekly intervals during early pregnancy. After conception, HCG levels rapidly increase, roughly doubling every 72 hours. HCG levels peak between weeks 8-11 of pregnancy, then start to decline and plateau for the remainder of the pregnancy.


The HCG Level Chart:


HCG Levels at 3 Weeks: 5 – 50 mIU/mL

HCG Levels at 5 Weeks: 18 – 7,340 mIU/mL

HCG Levels at 7-8 Weeks: 7,650 – 229,000 mIU/mL

HCG Levels at 9-12 Weeks: 25,700 – 288,000 mIU/mL


Quantitative HCG Testing


On top of peeing on a stick, you also may want to have a beta-HCG blood test done. Current technology for quantitative HCG testing uses blood work samples to provide an incredibly accurate measurement of your HCG level. This may be done to confirm pregnancy or to monitor HCG levels to ensure a healthy pregnancy.

High HCG Levels


It is not very common for women to have higher than average HCG levels during early pregnancy. High HCG levels can be caused by a variety of conditions and situations, such as:

  • You are further along in your pregnancy than you thought. Inaccurate conception date calculations can make it seem like your HCG levels are higher than they should be.


  • You’re having twins or triplets. The more embryos that are growing, the more HCG hormone is produced!


  • You are taking medications to help with fertility. Fertility medications are associated with increased HCG production.


Low HCG Levels

It is also possible to have lower than average HCG levels during pregnancy. This isn’t always a cause for alarm! Many women have healthy and normal pregnancies with lower-than-average HCG levels. However, having low HCG levels may be indicative of an underlying problem, such as:

  • A miscalculation in gestational age. If the conception date was later than assumed, it will appear like you have lower than average HCG levels. 


  • A possible miscarriage or the cessation of fetal development. If the fetus is no longer growing, HCG levels will begin to decrease.


  • An ectopic pregnancy. This is a serious condition where the fertilized egg implants in the fallopian tubes. As it continues to develop, it can cause the fallopian tube to rupture and cause internal bleeding. 

Limitations of HCG Testing


While having access to at-home HCG testing has been excellent for increasing accessibility to pregnancy testing, they are not always as helpful or accurate as we hope. Many HCG tests claim to be up to 99% accurate – but this is based on laboratory collected urine samples tested by professional technicians. User error in the home setting is common, and causes inaccurate readings. Additionally, HCG strips are not always able to detect low levels of HCG hormone. It is estimated that HCG tests need at least 12.4 mIU/mL of HCG to be present in the urine sample to produce a positive result. It is possible for women in their 4th week of pregnancy to test negative on HCG test strips if they have low HCG levels (this is a false negative).

Putting It All Together


HCG is an essential hormone in the development of a healthy fetus. HCG test strips can be helpful for identifying pregnancy – but they are not always accurate. While at-home monitoring options are accessible and easy to use, it is important to refer to your doctor if you have any concerns about your HCG levels during pregnancy.