What Exactly is Progesterone?

“Estrogen… testosterone… estrogen… testosterone…” We hear so much about the male and female sex hormones, their benefits, their problems (especially when the body under-produces them), and their potential as supplemental therapies.

But we hear too little about progesterone, a steroid hormone produced in the bodies of both men and women, but far more common in women. Many people know progesterone as one of the main active ingredients in “the pill,” but too few of us know what progesterone is and does. So let’s take a moment to appreciate this very important hormone.

What is Progesterone?

Progesterone is intimately involved in the menstrual cycle and pregnancy, and also has some important brain functions. Like estrogen, it is a steroid hormone. Unlike estrogen, however, progesterone is responsible for most of the changes that occur during pregnancy, like the growth of the uterus, the growth of secondary alveoli in mammary glands, and the ability of the uterus to hold the fetus in place.

Progesterone is produced in fairly limited supply prior to pregnancy, but increases dramatically as babies are brought to term. After delivery, progesterone levels are diminished. As with estrogen, the shutting down of the ovaries during menopause also shuts down progesterone production. Progesterone is still present in the body, because it is also produced in the adrenal gland and in trace amounts in the nervous tissue of the brain, but at much lower levels.1

When is Supplemental Progesterone Given?

 Progestin-therapy (in the form of a shot or a pill) is a funny conundrum: it has been shown to protect the uterus, but it also acts as a birth control mechanism as well as a first line treatment for abnormal bleeding conditions, notably endometriosis. Because progesterone (and related hormones) can actually act against estrogen, which is what causes the problematic cell growth that has become known as endometriosis, progestin-therapy has been shown to help some endometriosis sufferers. Too little progesterone is also always seen in those diagnosed with polycystic ovary syndrome, and supplemental progesterone—especially as a cream—are often prescribed to these people.2

The problem here is: when a person stops progestin-related contraceptives, the time it takes for the body to begin ovulating again varies significantly from person-to-person, making unwanted pregnancy a real risk. Another potential problem with progestin-therapy is that progesterone inhibits lactation, so a woman who is trying to nurse a baby and is experiencing abnormal bleeding may not want to risk progestin-therapy.

Other Important Functions of Progesterone

Progesterone has other important roles that deserve a shout-out: for about three decades, progesterone has been shown in clinical trials to contribute to a positive outcome for survivors of traumatic brain injury. Also, because progesterone enhances serontonin-receptors in the brain, it is being studied as a treatment for addiction, especially to nicotine. Finally, progesterone seems to help prevent endometrial cancer because of the way it interacts with estrogen.

What all this means to daily life will depend on your needs and issues. Should you take progesterone as a birth control method? What if you eventually want to have a baby and breastfeed successfully? Are you bleeding abnormally? Can progestine-therapy help? Would you be better off having an endometrial ablation and being done with it?

These are questions for you and your MIRI physician. In the meantime, let’s at least appreciate the elevated role that progesterone plays in the marvelous complexity of our bodies.

  1. You and Your Hormones. Progesterone. January 14, 2015. http://www.yourhormones.info/Hormones/Progesterone.aspx
  1. Women Living Naturally. PCOS and Progesterone. http://www.womenlivingnaturally.com/articlepage.php?id=106

Content Sponsored by: MIRI Women – The Minimally Invasive Reproductive Surgery Institute (MIRI) brings together highly skilled, board-certified specialists who are focused on women’s health. Our team of professionals is trained in advanced gynecology, specifically hysterectomy surgery. Philosophically, our partner physicians take a “less is more” approach to health care, by first treating patients with the most conservative therapies. MIRI focuses on physical healing, while emphasizing that a patient’s emotional well-being is just as important.

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