What is hCG?

hCG stands for human chorionic gonadotropin, a hormone that plays two important roles in fertility care. During treatment, it's used as a "trigger shot" to help your eggs reach their final stage of maturity before collection. Later on, it's the hormone a pregnancy test detects to confirm a pregnancy.

Towards the end of ovarian stimulation, your eggs need one final signal to mature fully before they're ready for collection. In a natural cycle, your body does this with a surge of luteinising hormone (LH). During treatment, we replicate that surge with an injection of hCG, often called a trigger shot.

hCG as the "pregnancy hormone"

Once an embryo implants in the uterus, the body begins producing hCG, which is why it's often nicknamed the pregnancy hormone. This is the hormone that both home pregnancy tests and clinical blood tests detect, and rising hCG levels are usually one of the first signs of a developing pregnancy.

Because a trigger shot also contains hCG, testing too soon after your injection can sometimes show a false positive, as traces of the medication may still be in your system. Your clinical team will let you know the right day to test, so your result is accurate.

If you're ever unsure about your trigger shot, its timing, or your test results, please speak with your clinical team. We're here to support you through every stage of your treatment.

Frequently asked questions

What does hCG stand for? Human chorionic gonadotropin.

Why is hCG used as a trigger shot? It replicates your body's natural hormone surge, helping your eggs complete their final maturation before collection.

Is hCG the same as the pregnancy hormone? Yes. hCG is produced naturally once an embryo implants, and it's what pregnancy tests detect.

Can I test for pregnancy too soon after my trigger shot? Yes, testing too early can give a false positive, since traces of the trigger medication may still be present. Your clinical team will advise the right day to test.