Why Progesterone Is A Must For Your Best Fertility

Like estrogen, progesterone is a female sex hormone essential for growing a healthy baby – so essential, in fact, that it’s been nicknamed “the pro-gestation hormone” because without adequate amounts, a pregnancy is unlikely to occur. In order for a pregnancy to happen, not only does an egg need to be released and fertilized, but the resulting zygote needs to implant itself in the uterine lining to develop and mature. Without progesterone, the uterine lining could not transform into the thick, cozy, and inviting habitat necessary for implantation. Progesterone also stimulates cell division of the zygote (aka baby’s first growth spurt), helps prevent miscarriages, and thickens cervical mucus to protect against bacterial infections. So yeah… progesterone is pretty important!

How Is Progesterone Made?

Like estrogen, the production of progesterone in the ovaries is regulated by an area of the brain called the hypothalamus. The hypothalamus releases a hormone called gonadotropin-releasing hormone (GnRH), which stimulates the anterior pituitary gland to secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSL). FSL tells the ovaries to produce estrogen, and LH tells the ovaries to produce progesterone. When the level of progesterone is high enough, GnRH production shuts down. And, men and women also make a little bit of progesterone in our adrenal glands. 

Throughout the menstrual cycle, estrogen and progesterone take turns being the dominant hormone: estrogen during the follicular phase of the cycle (the first half of the cycle before ovulation), and progesterone during the luteal phase of the cycle (the second half of the cycle after ovulation). If you’ve been utilizing the fertility awareness method (FAM) and have noticed a luteal phase lasting less than ten days, it’s time to get your progesterone levels tested. A short luteal phase is a common barrier to pregnancy because it doesn’t give the uterus enough time to thicken, decreasing the chances of successful implantation.

If you’re curious about which hormone tests are best for you, check out Pillar 2.4: Fertility Testing and Lab Interpretation, where I give you the lowdown on several types of tests on the market.

Why Wouldn’t I Have Enough Progesterone?

There are several reasons why someone might have low progesterone, including an underactive thyroid, PCOS, increased levels of the hormone prolactin, and low cholesterol, but our main focus is going to be on stress and the adrenal glands.[1]

The adrenals are two little glands that sit on top of your kidneys, regulating your metabolism and your response to stress. When your brain detects danger, your adrenals release the hormone cortisol, signaling your body to activate what I like to call “no place for a baby” mode: your liver releases glucose into the bloodstream, your digestion slows, and blood is shunted away from your reproductive organs. The pituitary gland also becomes less responsive to GnRH, reducing the secretion of LH and in turn, reducing the output of progesterone.

Back in the day when humans were hunting for their food and trying not to be prey themselves, this boost of cortisol helped them fight or flee to survive life-or-death situations. Once the stressor went away – we escaped the lion or caught the deer, say – cortisol levels returned to normal and reproductive function was restored.

Flash-forward to today’s world, and we have a totally different story. Your stress response can be activated on a chronic low-grade level for many hours a day, week after week, without ever getting shut off, trapping the body in “no place for a baby” mode. Think frustrating stop-and-go traffic on your daily commute, back-to-back work deadlines with no end in sight, swiping through your social media feed and comparing yourself to everyone and their mom 24/7 – even those “healthy” exercise and nutrition habits that you’ve been working so hard to implement can elicit a stress response if they aren’t right for your unique situation. 

These may not seem like life-or-death, fight-or-flight situations to you, but unfortunately the brain and body perceive them as such, and it may be keeping you locked in sympathetic dominance if you don’t do anything to stop it. Some people equate a high-stressed, “sleep-when-you’re-dead” lifestyle with being a high performing, goal-oriented overachiever, but it can come at a significant cost to your health and fertility.

Signs You Might Not Have Enough Progesterone

The most obvious signs of low progesterone are irregular menstrual periods and short luteal phases, which are easiest to spot if you track your cycle using FAM. Other signs of low progesterone include: 

  • Low libido
  • Hot Flashes
  • Vaginal dryness
  • Frequent breast soreness
  • Spotting before your period
  • Depression, anxiety, or mood swings
  • Frequent headaches

 

If you’re unsure if low progesterone may be affecting your fertility, my free Root Cause Quiz will help you dial in on the sneaky stressors, environmental factors, and hormone imbalances that can lead to subfertility.   

How To Improve Progesterone Levels

Stress Management

 

As we discussed above, chronic stress can play a major role in subfertility, increasing cortisol, and creating hormone imbalances. If you have PCOS, chronic stress can play an even greater role, as high levels of cortisol worsen insulin resistance, which in turn increases testosterone production.

Managing stress is often easier said than done, but managing stress does not mean eliminating stress. There will always be stress in our lives, we just need to develop coping mechanisms that improve our fertility rather than suppress it.  

 

  • Movement is a great way to let off some steam while increasing endorphins and supporting muscle and bone health. I use the term “movement” rather “exercise” to emphasize that any movement – dancing, walking, stretching, gardening – supports mental and physical health, not just cycling classes and HIIT. Just keep in mind that compulsive exercise – exercise done as a punishment for “unhealthy” eating, over-exercise that leads to injury, exercise that interferes with other important areas of your life – creates stress rather than relieves it. The important thing is to find something you enjoy doing.
  • Getting enough sleep might not seem like a coping mechanism, but if you’re anything like me, you might’ve noticed that your snapping point is much lower when you’ve only had a few hours of sleep versus when you’ve gotten a full night’s rest. Lack of sleep also contributes to mood disorders like depression and anxiety, which can further heighten the feeling of stress.[2]
  • Making time for self-care might sound unimportant when you’ve got meetings to attend, papers to grade, or a full social calendar, but taking time to slow down and nurture your mind and body can significantly improve stress levels.[3] This could be anything from playing with your pet for 15 minutes, taking a soothing bubble bath, reading before bed, getting a massage, learning to meditate, or simply enjoying a cup of hot tea with no distractions.
  • Increase your social support by joining the Fueling Fertility Tribe, where you can ask questions, voice concerns, and connect with others going through similar ups-and-downs of the fertility journey.

 

Adequate Nutrition

 

  • All of your sex hormones are made from cholesterol. This means that if you’re eating a diet low in fat, specifically saturated fat, you might not be supporting optimal hormone production. For decades, researchers linked high intakes of saturated fat with increased risk for heart disease, but recent research suggests that this connection might not be as linear as it once seemed. What does this mean for your fertility? Enjoy saturated fats, which come primarily from animal products like meat and dairy, but try to choose grass-fed options when you can. Grass-fed products are more nutrient-rich and have a better balance of saturated to unsaturated fats than conventionally produced animal products.
  • Support your blood sugar by eating foods high in inositol, which can improve insulin resistance and proper hormone production.[4] These include fresh fruits and vegetables, beans, whole wheat bread, and, if you can stomach it, liver products.[5]


Again, there are many different underlying conditions that can cause low levels of progesterone, such as hypothyroidism, PCOS, or leaky gut. That’s why it is critical that you find your unique root cause(s). My Hormone Fix Bundle dives deep into the root causes of hormone imbalances, looking at sneaky stressors, nutrition, gut health, lab testing, and more to help you achieve hormone harmony.

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