Progesterone is an endogenous steroid hormone that is commonly produced by the adrenal cortex as well as the gonads, which consist of the ovaries and the testes. Progesterone is also secreted by the ovarian corpus luteum during the first ten weeks of pregnancy, followed by the placenta in the later phase of pregnancy.

What is the main source of progesterone?

Although the corpus luteum in the ovaries is the major site of progesterone production in humans, progesterone is also produced in smaller quantities by the ovaries themselves, the adrenal glands and, during pregnancy, the placenta.

Where does the main source of progesterone come from?

Progesterone is produced by the ovaries, placenta, and adrenal glands. The term progestin is used to describe progesterone and synthetic steroid hormones with progesterone-like properties, such as the progestogen levonorgestrel. In the ovaries the site of progesterone production is the corpus luteum.