Human Chorionic Gonadotropin (HGC)

Sometimes called the ‘pregnancy hormone’ is the key hormone during pregnancy. It’s produced by what ultimately becomes the placenta. The basic job of HCG is telling a woman’s body that there’s a life form growing in her womb and that her body needs to build a nest for it. HCG also tells the ovaries to shut off the production line of maturing an egg every month. HCG levels rise eight days after ovulation, peak at 60 to 90 days, and then lower slightly, leveling off for the remainder of the pregnancy. Typically, during the first 10 weeks of your pregnancy, HCG levels double every two days.HCG circulates through the body and is eliminated in the urine (which is what over the counter pregnancy tests are looking for — a high concentration of beta HCG in the urine that indicates you are, indeed, pregnant).

Source: https://www.parents.com/pregnancy/my-life/emotions/a-cheat-sheet-to-pregnancy-hormones/