What is human chorionic gonadotrophin?

Human chorionic gonadotrophin (hCG) is a hormone produced by the placenta during pregnancy. It’s sometimes called the pregnancy hormone because of its unique role in supporting a pregnancy. HCG is found in your urine or blood around 10 to 11 days after conception (when a sperm fertilizes an egg). Your hCG levels are the highest towards the end of the first trimester (10 weeks of pregnancy), then decline for the rest of your pregnancy. Healthcare providers measure hCG to confirm a pregnancy and provide details on how the pregnancy is progressing.

How is human chorionic gonadotropin produced?

After conception occurs, a fertilized egg travels through your fallopian tubes to your uterus. The fertilized egg (called an embryo) implants (attaches) into the wall of your uterus. This triggers the placenta to form. Your placenta begins producing and releasing hCG into your blood and urine. HCG can be found in a person’s blood around 11 days after conception. It takes slightly longer for hCG to register on urine tests.

HCG increases quickly (almost doubling every three days) for the first eight to 10 weeks of pregnancy. Healthcare providers look at how quickly a person’s hCG levels rise in early pregnancy to determine how the pregnancy and fetus are developing.

What does human chorionic gonadotropin do?

Once your placenta begins making hCG, it triggers your body to create more estrogen and progesterone. Together with hCG, these hormones help thicken your uterine lining and tell your body to stop menstruating (or releasing eggs). The correct balance of these three hormones sustains and supports the pregnancy.