This steroid is heavily involved in the reproductive system, during pregnancy, and during
the early stages of human embryo development.

Progesterone – similar to other steroid hormones – is derived from cholesterol.
It’s action is closely related to another sexual hormone – estrogen.

This steroid is produced in several areas:

- Ovaries
- Gonads
- Placenta (during pregnancy)
- Brain

Production is initially in the corpus luteum of the ovary. One the embryo
begins to development the production will switch to the placenta. This occurs around the 8th week.

The level of progesterone found in women

1.) Relatively low prior to menstruation
2.) Relatively low during the Follicular Phases
3.) Increases following ovulation the Luteal Phase

4.) If pregnancy is not achieved then progesterone levels will decrease.
5.) If pregnancy is achieved – progesterone levels will be maintained

Functions of Progesterone:

- Allows the conversion on endometrium so that implantation of the embryo
may take place

- Affects the mucus in vaginal region to become thick

- Causes the decrease of contractions of the uterine smooth muscle

- Inhibits lactation during pregnancy

- May inhibit labor

- May prevent endometrial cancer

- other

* Progesterone itself is often synthesized in the form of medications for
In-Vitro Fertilization, Birth control, to help with bleeding, and others