Progesterone

Important facts about Progesterone

Progesterone is one of the steroid hormones that stimulates and regulates important functions. It is produced in the ovaries. It is secreted by the corpus luteum and by the placenta and is responsible for preparing the body for pregnancy and, if pregnancy occurs, maintaining it until birth. If pregnancy does not occur, estrogen and progesterone levels drop, the endometrium breaks down and menstruation occurs.

If a pregnancy occurs, progesterone is produced in the placenta, and levels remain elevated throughout the pregnancy. The placenta begins to secrete progesterone which supplements that of the corpus luteum. The combination of high estrogen and progesterone levels suppress further ovulation during pregnancy.

A drop in progesterone levels is possibly one step that facilitates the onset of labor. Progesterone decreases contractility of the uterine smooth muscle. Progesterone also encourages the growth of milk-producing glands in the breast during pregnancy.

Progesterone levels are relatively low in children and postmenopausal women. Adult males have levels similar to those in women during the follicular phase of the menstrual cycle.

High progesterone levels are believed to be partly responsible for symptoms of premenstrual syndrome (PMS), such as breast tenderness, feeling bloated and mood swings.

Progesterone also serves several other important functions in the body. It aids in immunity, reduces swelling and inflammation, stimulates and regulates the production of the thyroid gland, and keeps blood-clotting levels at normal values.

Hormone Replacement Therapy