Human Chorionic Gonadotropin Hormone (HCG)
Ever wonder how at-home pregnancy tests are able to detect if you are pregnant? The Human Chorionic Gonadotropin (HcG) hormone is important in the early stages of pregnancy. It is produced by cells that are surrounding a growing embryo, which eventually forms the placenta. HcG can be detected in your body as early as 1 week after an egg is fertilized, which forms the basis of most over the counter pregnancy tests. HcG also ensures the corpus luteum, a temporary endocrine gland a woman’s body produces after ovulation, continues to produce progesterone during the first trimester of pregnancy. Low concentrations of HcG are also produced by the pituitary gland, thus, men and non-pregnant women still have detectable levels of HcG throughout their lives.
What does HcG do?
The levels of HcG increases every two to three days as your embryo continues to develop. HcG levels peak around the sixth week of pregnancy. Afterwards, HcG will be found in your body, but the levels will begin to decrease. Once the placenta is fully formed, it serves as a source of progesterone production and assistance from HcG to support ovarian function is no longer essential.
What problems can occur with HcG?
Very high HcG levels are rare. In these cases, it may be sign of a molar pregnancy, which is an abnormal growth of cells that usually develop in the placenta. In people who are not pregnant, high HcG levels may be due to certain cancers such as breast, kidney, and lung.
Low levels of HcG may be a sign of a miscarriage or another problem within the pregnancy, such as the embryo implanting outside of the uterus.
Questions to ask your healthcare team
- How early can doctors detect my HcG levels?
- What test is the best way to detect pregnancy?
- Why is HcG important in the early stages of my pregnancy?
Edited: January 2019
Editors: Irina Bancos, MD