If you’ve ever taken a pregnancy test, hCG is the hormone that’s measured to see if you’re pregnant. Additionally, hCG is a key indicator as to how your pregnancy is developing – and it can pinpoint any potential complications, e.g. an ectopic pregnancy or blighted ovum.
Knowing the role of hCG in your body when you become pregnant allows you to understand how your pregnancy is progressing, and what to expect as your hCG levels change over time.
hCG stands for human chorionic gonadotropin. It’s formed and secreted by your placenta after implantation.
These hCG levels begin to rise and encourage the production of progesterone by sending a message to your corpus luteum. The corpus luteum is a temporary structure that develops in your ovaries during pregnancy to produce high levels of progesterone. In turn, the higher levels of progesterone support your growing embryo by preventing the shedding of your uterine lining. For this reason, you may hear the signals of hCG being referred to as, “the rescue of the corpus luteum.”
A pregnancy test uses what’s known as a sandwich enzyme immunoassay technique to detect rising changes in your hCG hormone.
While this technique may sound incredibly complicated, it truly isn’t.
There are two main components to hCG: an alpha and beta part. A pregnancy test contains two special antibodies that detects both parts. If you’re pregnant when you urinate onto the stick, the antibodies will sandwich the hCG between them. This triggers the dye that creates the positive dark line on the pregnancy test. The second line is simply an indication as to whether these antibodies are working.
An hCG level above 25mIU/mL tends to indicate a positive pregnancy, while negative results are anything below 5mIU/mL. Levels of hCG are first detected approximately 11 to 14 days after conception by a blood or urine test.
In typical cases, hCG levels double every 2 to 3 days until they peak after 8 to 11 weeks. Then, they will drop off before plateauing for the rest of your pregnancy. Likewise, it’s no coincidence that the period during which your hCG level rises is often when morning sickness occurs.
However, it’s important to note hCG numbers themselves shouldn’t hold too much weight. Sometimes low values of hCG are normal during pregnancy. Rather, it’s the doubling of the hormone that’s more important.
Your hCG levels are only monitored through a serial beta hCG test if your pregnancy is:
· high risk
· occurs after a number of miscarriages
· compromised by severe cramping or some bleeding
There are a few potential causes of low hCG levels – something your doctor will be able to investigate and discuss with you further.
In contrast, high hCG levels may indicate entirely different causes, including:
Checking these higher levels every 2 or 3 days to see if anything changes is very important.
Approximately 4 to 6 weeks after losing your pregnancy, your hCG levels should start to return to their pre-pregnancy range. The time and type of loss (natural delivery, abortion, D & C procedure, or spontaneous miscarriage) can cause a differentiation in how long it takes your levels to return to normal.
To ensure the levels return to < 5.0mlIU/mL, many healthcare providers will continue to monitor your hCG levels for several weeks after your pregnancy loss.
If your pregnancy test indicates a positive result, it’s highly likely you’re pregnant. It’s extremely rare to get a false positive. However, some conditions can result in these false readings, including early miscarriage and certain types of cancer. Also, some types of antibodies can affect the results.
Medications used for fertility treatments that contain hCG may also interfere with your hCG levels. All other types of medication, e.g. contraception, pain relievers, antibiotics, and hormone medication shouldn’t affect an hCG test.
While home pregnancy tests are incredibly accurate and can detect higher-than-normal levels of hCG, they’re unable to indicate your exact hCG levels.
Generally speaking, you should expect the lines on your pregnancy test to get darker the further along you are in your pregnancy. However, testing too often can lead to negative results, as there hasn’t been enough time for the hCG to accumulate in your urine.
Ultimately, hCG is a great indicator of successful conception and can be used to effectively monitor the progression of your pregnancy. Thankfully, routine checking of your hCG levels won’t be necessary unless doctors want to monitor for any potential complications.