FAQs About Progesterone
Fertility and menstruation are largely controlled by hormones, and one of these hormones is progesterone. Progesterone is a bioidentical hormone meaning it is identical to what the body produces. Progesterone is a steroid hormone belonging to a class of hormones called progestogens. It is secreted by the corpus luteum of the ovary, during the second half of the menstrual cycle in a menstruating female. It is also secreted by the placenta during pregnancy and by the myelin sheaths around our nerves to protect our nervous system.
Progesterone is an upstream precursor to most of our other steroid hormones, all of which are derived from cholesterol (yes, there are good things about cholesterol!). These hormones include cortisol, DHEA, androstenedione, estrogen and even testosterone. In a normally cycling female, the corpus luteum in the ovary produces approximately 20 to 30 mg of progesterone daily during the second half (luteal phase) of the menstrual cycle. There are progesterone receptors throughout the body that respond to the circulating progesterone in a myriad of ways.
Progesterone in the body is considered a calming hormone. In the brain, progesterone metabolites can bind to GABA receptors, mimicking GABA, our primary calming neurotransmitter. In contrast, estrogen is considered “excitatory”. Estrogen dominance can lead to too much stimulatory effect which can present as difficulty staying asleep.
A clear way of knowing whether you have low progesterone is to get your levels tested. Additionally certain signals indicating low progesterone levels may include an irregular menstrual cycle, fertility issues, unexplained mood changes, bloating, breast tenderness, disrupted sleep, and heavy menses.
As women age the ratio of progesterone to estrogen decreases causing a range of symptoms that could include weight gain, hot flashes, reduced libido, mood swings, low mood, sleep difficulties, fatigue and vaginal dryness. Improving the progesterone to estrogen ratio by shoring up progesterone levels can help bring a woman back into balance.
There are many external factors that can contribute to periods stopping and starting. For example, it is common for women to skip a menses during times of stress as well as when exercising a lot or after significant weight loss. Menstruation is mostly related to estrogen levels. The higher the estrogen, the greater the buildup of the endometrial lining and hence the greater amount of bleeding. Progesterone is a hormone that normally rises AFTER ovulation.
The menstrual cycle occurs in three phases: the follicular phase, ovulation, and the luteal phase. On the first day of your cycle, which is the first day of your period, progesterone levels are low. During the middle of the luteal phase, progesterone secretion rises to an average of 25mg daily. At the end of the cycle a drop in both estrogen and progesterone contribute to the shedding of the endometrial lining, or menstruation. If pregnancy occurs during the cycle, the body maintains estrogen and progesterone production, thus retaining the endometrium to support the pregnancy.
During early pregnancy, progesterone is secreted by the corpus luteum in the ovaries to help maintain the endometrium (uterine lining) to support a fertilized egg. At about 8-12 weeks after fertilization the body shifts responsibility from the corpus luteum to the placenta for progesterone production. By the third trimester, the placenta can produce upwards of 300 mg per day of progesterone. After delivery, hormone levels drop precipitously and can remain low during breastfeeding. It may take 3-6 months after delivery to start menstruating again.
Of all the hormones the body makes, progesterone has the widest range. For example, the body can go from making 25 mg or less daily during the second half of the cycle to over 300 mg per day during pregnancy. Our bodies can accommodate a range like this as the liver is well equipped to manage the rapid breakdown of progesterone if levels get too high. This is not the same as synthetic progestins, which were designed to avoid rapid clearance by the liver.
There are conditions in which the body can make too much progesterone, but they are rare. If you are concerned you may be producing too much progesterone, we recommend you talk to your doctor and get your hormone levels tested or test your levels yourself through a reputable home hormone testing lab.
Weight gain is caused by an assortment of hormones that relate to hunger, stress, metabolism, and more. Progesterone alone does not cause weight gain. Progesterone is associated with an increase in body temperature, which can reflect an increase in metabolism, but increases in metabolism can also drive the body to want more food. In short, it’s complicated.
If you are looking to lose or gain weight, discuss this with a professional who can help you evaluate all the different influencers to see what might be impacting you reaching your goals. Progesterone is likely only one piece of the puzzle.
Estrogen dominance is a term that describes a condition where the normal balance of estrogen to progesterone is changed by excess estrogen or inadequate progesterone.
Women suffering from pre-menstrual difficulties to women experiencing the effects of menopause will recognize the hallmark symptoms of estrogen dominance, which can include weight gain, bloating, mood swings, irritability, tender breasts, headaches, fatigue, mood swings, blood sugar imbalances, and fibrocystic changes, to name a few.