Progesterone is another important female hormone. We have seen that it works in close conjunction with estrogen.

Produced in the corpus luteum (the follicle that ruptures during ovulation), the adrenal glands, and in the placenta during pregnancy, progesterone plays a crucial role in a woman's menstrual cycle. It is instrumental in bringing about changes in the uterus, changes that prepare the uterus lining for the reception of a fertilized egg. Where fertilization does not occur, the progesterone levels drop, causing the prepared lining of the uterus to be sloughed off.

Progesterone is largely responsible for mood swings associated with the menstrual cycle that some women are subject to. It is the low level of progesterone just prior to menstruation that is responsible for bringing on the symptoms of PMS experienced by these women. By undergoing treatment that brings both progesterone and estrogen to normal levels, many women have found relief from these pre menstrual mood swings.

As women get into their late 30's their progesterone levels decrease. As they go into menopause, these levels then tend to fluctuate wildly. These fluctuating levels of progesterone, combined with low levels of estrogen, bring on the various symptoms of menopause. By bringing the levels of both hormones into balance, and back to levels found in pre-menopausal women, these menopausal symptoms, for many women, have been reduced or eliminated.

If menopausal symptoms continue, with normal progesterone and estrogen levels, then many women turn to Primrose Oil, Black Cohosh (Remifemin) or clonidine (Dixarit) to control symptoms of flushing and sweats.

Another important facet of progesterone's activity is its strong involvement in a woman's sex drive. Progesterone is the hormone thought to exercise the strongest influence in this regard - in conjunction with testosterone - and progesterone is considered to produce the heightened libido many women experience after ovulation.