"Your progesterone is low."


For many women, hearing those words raises more questions than answers.


Does it mean you won't be able to get pregnant?


Do you simply need progesterone supplementation?


Is your body no longer producing enough hormones?


These are some of the most common concerns I hear from women trying to conceive and from women navigating the hormonal changes of perimenopause.


While progesterone supplementation certainly has an important place in fertility treatment and hormone therapy, I've found that many women are never told why their progesterone is low in the first place.


That's where functional medicine takes a different approach.


Instead of asking, "How do we increase progesterone?"


I first ask, "Why isn't your body producing enough progesterone naturally?"


Because progesterone isn't produced randomly. It's the result of a carefully coordinated conversation between your brain, ovaries, thyroid, adrenal glands, metabolism, and immune system. When progesterone is low, it's often your body's way of signaling that something upstream deserves attention.


Rather than viewing low progesterone as the diagnosis, I see it as an important clue. Understanding that clue can make all the difference, not only for improving fertility, but also for supporting healthy menstrual cycles, reducing PMS, improving sleep, easing perimenopausal symptoms, and promoting long-term hormonal health.


In this article, we'll explore what progesterone does, why it matters, and the most common reasons your body may not be producing enough of it.


What Is Progesterone?

Progesterone is a hormone primarily produced by the corpus luteum, a temporary gland that forms in the ovary after ovulation. If pregnancy occurs, the developing placenta gradually takes over progesterone production towards the end of the first trimester. If pregnancy does not occur, progesterone levels naturally decline, triggering the start of your menstrual period.


This is why healthy progesterone production depends on healthy ovulation. Without ovulation, there is no corpus luteum, and without a corpus luteum, your body cannot produce meaningful amounts of progesterone.


Although progesterone is often referred to as the "pregnancy hormone," its effects extend throughout the body.

Progesterone helps:

  • Prepare the uterine lining for implantation
  • Support early pregnancy
  • Regulate the second half (luteal phase) of the menstrual cycle
  • Raise basal body temperature after ovulation
  • Support healthy sleep and relaxation through its effects on the brain
  • Balance some of estrogen's effects on the uterine lining
  • Support breast, bone, and nervous system health

Because progesterone influences so many different systems, low levels can contribute to symptoms that extend far beyond fertility.


Signs and Symptoms of Low Progesterone

Low progesterone doesn't look the same for every woman. Some women experience obvious menstrual changes, while others may not discover an issue until they're struggling to conceive or experiencing recurrent miscarriage.

Common symptoms may include:

  • Difficulty getting pregnant
  • Recurrent early pregnancy loss
  • Spotting before your period
  • Short luteal phases
  • Irregular menstrual cycles
  • Heavy menstrual bleeding
  • Increased PMS symptoms
  • Breast tenderness
  • Trouble falling asleep or staying asleep
  • Increased anxiety or feeling "wired but tired"
  • Mood changes
  • Headaches around the menstrual cycle
  • Hot flashes or night sweats, particularly during perimenopause

It's important to remember that these symptoms are not specific to progesterone deficiency alone. Many other hormonal and metabolic conditions can produce similar symptoms, which is why a comprehensive evaluation is often necessary rather than relying on symptoms alone.


Why Is My Progesterone Low?

One of the biggest misconceptions about progesterone is that it's a hormone we simply need to "boost." In reality, progesterone isn't produced in isolation. It's the end result of a healthy, coordinated reproductive cycle. Think of progesterone like the final chapter of a book. If something goes wrong in the earlier chapters, the ending changes too.

When I see low progesterone in my practice, I don't immediately focus on replacing it. Instead, I become curious about why the body wasn't able to produce enough progesterone naturally.


Here are some of the most common reasons:

1. You Didn't Ovulate (or Didn't Ovulate Well)

This is by far the most common reason progesterone is low.

Progesterone is produced by the corpus luteum, a temporary hormone-producing gland that forms after an egg is released from the ovary.

No ovulation = no corpus luteum = very little progesterone.

Sometimes ovulation doesn't occur at all (anovulation), while other times the follicle may release an egg but not develop into a strong, healthy corpus luteum capable of producing adequate progesterone.

This is why I rarely interpret a progesterone level by itself. I also want to know:

Are you confirming ovulation with basal body temperature, LH testing, or ultrasound?

How long is your luteal phase?

Are you spotting before your period?

Are your cycles becoming irregular?

These clues help us understand whether progesterone is truly the problem, or simply reflecting an issue with ovulation itself.


2. Poor Follicle Development

This is one of the most overlooked aspects of progesterone production. Many people think progesterone is only a "luteal phase hormone." But in reality, healthy progesterone begins with a healthy follicle.

During the first half of your menstrual cycle, a follicle grows within the ovary. Inside that follicle is the egg.

After ovulation, that same follicle transforms into the corpus luteum, which becomes your body's primary source of progesterone. If the follicle never develops optimally, the corpus luteum may not function optimally either.

In other words, today's progesterone is often influenced by what happened two weeks earlier during follicle development.


Follicle quality can be affected by many factors, including:

  • Age-related changes in ovarian reserve
  • Oxidative stress
  • Poor mitochondrial function
  • Chronic inflammation
  • Nutrient deficiencies
  • Reduced blood flow to the ovaries

This is one reason why I often first focus on supporting overall egg and follicle health rather than looking only at progesterone levels.


3. Thyroid Dysfunction

The thyroid and reproductive hormones are deeply connected.

Even subtle thyroid dysfunction can interfere with communication between the brain and ovaries, affecting ovulation and ultimately progesterone production.

Women with hypothyroidism or autoimmune thyroid disease may experience:

  • Irregular cycles
  • Delayed ovulation
  • Short luteal phases
  • Difficulty conceiving
  • Increased risk of miscarriage


While many women are told their thyroid is "normal," a basic TSH test doesn't always provide the full picture. In my practice, I often evaluate a more comprehensive thyroid panel (including free T3, free T4, thyroid antibodies, and other markers) to better understand how thyroid health may be influencing fertility.


4. Chronic Stress and HPA Axis Dysfunction

You've probably heard the advice, "Just relax."

Unfortunately, fertility is far more complex than that.

Your brain constantly gathers information about your environment. If it perceives that your body is under chronic stress, whether from emotional stress, poor sleep, under-eating, overtraining, chronic illness, or inflammation, it may temporarily prioritize survival over reproduction.

This communication occurs through the hypothalamic-pituitary-ovarian (HPO) axis, the hormonal network that regulates ovulation.

When that communication becomes disrupted, ovulation may become delayed, inconsistent, or absent, leading to lower progesterone production.

This doesn't mean stress is "all in your head." It means your nervous system and reproductive system are closely connected.

Supporting restorative sleep, adequate nutrition, blood sugar balance, and nervous system regulation can all play an important role in supporting healthy ovulation.


5. Inflammation and Chronic Illness

Inflammation doesn't just affect your joints or immune system, it can also affect reproductive hormones.

Conditions such as:

  • Endometriosis
  • Autoimmune disease
  • Chronic infections
  • Mold exposure
  • Gut dysfunction
  • Elevated homocysteine
  • Insulin resistance

may all contribute to an inflammatory environment that interferes with healthy ovarian function.

Rather than asking, "How do we raise progesterone?" we sometimes need to ask,

"What is creating enough physiological stress that the ovaries aren't functioning optimally?"

Reducing inflammation isn't about perfection. It's about identifying and addressing the underlying factors that may be placing additional strain on the body.


Related articles:

The Fertility Factor Most Women Never Hear About: The Vaginal Microbiome

What Is Homocysteine and Why Does It Matter for Fertility?


6. Nutrient Deficiencies

Hormones are built from nutrients.

If your body doesn't have the building blocks it needs, hormone production may become less efficient.

While there isn't a single "progesterone vitamin," several nutrients play important roles in ovulation, hormone synthesis, and corpus luteum function, including:

  • Vitamin B6
  • Magnesium
  • Zinc
  • Vitamin C
  • Healthy dietary fats
  • Adequate protein

Nutrition alone isn't the answer to every hormone imbalance, but it creates the foundation upon which healthy hormone production depends.

That's why I rarely recommend supplements based on one lab value alone. Instead, I look at the bigger picture to understand which systems may need additional support.


Can You Increase Progesterone Naturally?

If you've been told your progesterone is low, your first instinct may be to search for ways to "boost" it naturally.

While certain supplements and lifestyle changes may support progesterone production, it's important to understand that your body can't produce more progesterone unless healthy ovulation occurs first.

This is why I encourage my patients to think beyond simply raising a hormone level. Instead, we focus on creating the conditions that allow the body to ovulate well and produce progesterone naturally.


Depending on the underlying cause, that may include:

  • Supporting Healthy Ovulation

Because progesterone is produced after ovulation, improving ovulatory function is often the first priority.

This may involve optimizing nutrition, improving sleep, supporting thyroid health, reducing inflammation, improving insulin sensitivity, or addressing chronic stress.

  • Nourishing the Body

Hormone production requires adequate calories, protein, healthy fats, vitamins, and minerals.

Restrictive dieting, under-eating, excessive exercise, or chronic nutrient deficiencies can all interfere with reproductive hormone production.

  • Improving Blood Sugar Balance

Insulin plays an important role in ovarian function.

For some women, particularly those with polycystic ovary syndrome (PCOS) or insulin resistance—stabilizing blood sugar can improve ovulation and support healthier progesterone production.

  • Reducing Inflammation

Inflammation can disrupt communication between the brain and ovaries while increasing oxidative stress throughout the reproductive system.

Addressing gut health, supporting the vaginal microbiome, treating chronic infections when present, and identifying environmental exposures such as mold may all play an important role for certain individuals.

  • Supporting the Thyroid

Healthy thyroid function is essential for regular ovulation.

If thyroid hormones are suboptimal, simply adding progesterone may not fully address the underlying issue.


When Supplements May Help

Depending on your individual situation, certain supplements may support ovulation and hormone production. These may include nutrients such as vitamin B6, magnesium, zinc, vitamin C, omega-3 fatty acids, or botanicals like Vitex in carefully selected cases.

However, supplements should never replace a thorough evaluation. The best protocol depends on why progesterone is low in the first place.

There is no one-size-fits-all solution.


What If Low Progesterone Is Part of Perimenopause?

If you're in your late 30s or 40s, declining progesterone may not simply be related to fertility, it may also be part of the natural hormonal transition known as perimenopause.


One of the earliest hormonal changes during perimenopause is that ovulation becomes less predictable.


Some cycles may be completely normal.


Others may involve delayed ovulation, weaker ovulation, or no ovulation at all.


Because progesterone is only produced after ovulation, these changes often lead to fluctuating progesterone levels long before menopause begins.


This helps explain why many women begin experiencing symptoms such as:

  • More frequent PMS
  • Shorter or irregular cycles
  • Spotting before a period
  • Heavier menstrual bleeding
  • Difficulty sleeping
  • Increased anxiety or irritability
  • Breast tenderness
  • Hot flashes or night sweats
  • Changes in fertility

Although these hormonal shifts are a normal part of reproductive aging, they shouldn't automatically be dismissed as something you simply have to tolerate.


Many women assume that once they reach their 40s, feeling exhausted, sleeping poorly, or experiencing worsening PMS is just "part of getting older."


Emerging research also reminds us that progesterone isn't just a reproductive hormone, it also plays an important role in the brain. Progesterone receptors are found in regions involved in memory, learning, mood, and executive function, and progesterone is converted into the neurosteroid allopregnanolone, which helps regulate calming GABA pathways. As progesterone production becomes less consistent during perimenopause, some women report symptoms such as brain fog, difficulty concentrating, changes in memory, increased anxiety, and disrupted sleep. While these symptoms are likely influenced by multiple factors, including fluctuating estrogen, sleep quality, and overall brain health, the changing effects of progesterone on the brain are an active area of research


In reality, while ovarian aging certainly influences hormone production, other factors, including thyroid health, insulin resistance, chronic inflammation, nutrient deficiencies, stress, and lifestyle, can significantly affect how smoothly you move through this transition.


Understanding these factors allows us to develop a more personalized plan that supports your hormones, rather than simply chasing symptoms.


Whether your goal is pregnancy or simply feeling like yourself again, understanding why progesterone is changing is often the most valuable place to begin.


Maria's Clinical Insight

Progesterone is rarely the beginning of the story.

More often, it's the final chapter, the result of everything that happened earlier in the cycle.

That's why my goal isn't simply to normalize a lab value. It's to understand the biology behind it.

When we identify and address the underlying factors affecting hormone production, we aren't just supporting progesterone, we're supporting the entire reproductive system.

Whether you're trying to conceive or navigating perimenopause, your hormones deserve more than a quick fix. They deserve to be understood.


When Should You Test Your Progesterone?

Timing matters.

Progesterone is produced after ovulation, so testing it too early in the cycle can make a completely healthy progesterone level appear low.

Many people have heard that progesterone should be tested on "day 21," but this is only accurate for women who ovulate around day 14 of a 28-day cycle. Instead of relying on a calendar day, progesterone is best measured approximately 5–9 days after ovulation, with many clinicians targeting about 7 days past ovulation (7 DPO), when progesterone levels are expected to peak.


This is one reason I often encourage women to track ovulation using methods such as basal body temperature, LH testing, or fertility monitors. Knowing when you actually ovulate allows hormone testing to be interpreted much more accurately.


Just as important as the progesterone value itself is the bigger picture. I rarely evaluate progesterone in isolation. Depending on your symptoms and goals, I may also recommend assessing markers such as thyroid function, estradiol, LH, FSH, insulin, inflammation, iron status, vitamin D, and other biomarkers that help explain why progesterone may be low.


The Bottom Line

Progesterone is much more than the "pregnancy hormone." It's a reflection of healthy ovulation and an important indicator of your overall reproductive health.

If your progesterone is low, it's worth asking a different question.


Not simply, "How do I raise my progesterone?"

But rather, "Why isn't my body making enough progesterone?"


For some women, the answer may be inconsistent ovulation. For others, it may involve thyroid dysfunction, inflammation, insulin resistance, nutrient deficiencies, chronic stress, or the natural hormonal changes of perimenopause.


Understanding the underlying cause allows us to move beyond simply treating a number on a lab report. It helps us create a personalized plan that supports your body's natural hormone production, improves fertility, and promotes long-term hormonal health.


Your hormones are always communicating with you. Learning how to listen is often the first step toward lasting change.


Frequently Asked Questions

Can you get pregnant with low progesterone?

Yes. The answer depends on why your progesterone is low. Some women have slightly lower levels but still ovulate normally and conceive without difficulty. Others may have low progesterone because they are not ovulating consistently or because another underlying condition is affecting reproductive health. Identifying the cause is essential.


Should I take progesterone supplements if my level is low?

Progesterone supplementation can be an important part of fertility treatment and pregnancy support for some women. However, supplementation doesn't always address the underlying reason progesterone is low. A comprehensive evaluation can help determine whether progesterone therapy is appropriate and what other factors should also be addressed.


Can stress lower progesterone?

Chronic physical or emotional stress can influence the communication between the brain and ovaries, affecting ovulation and, ultimately, progesterone production. Stress is rarely the only cause, but it is one piece of the overall picture.


Does low progesterone always mean I'm not ovulating?

Not necessarily. Some women ovulate but produce less progesterone than expected because the corpus luteum isn't functioning optimally. Others may not be ovulating at all. This is why evaluating ovulation patterns and cycle history is so important.


Is low progesterone normal during perimenopause?

As women enter perimenopause, ovulation often becomes less predictable. Because progesterone is only produced after ovulation, progesterone levels commonly begin to fluctuate and gradually decline during this transition. While this is a normal part of aging, severe symptoms shouldn't simply be ignored, as other treatable factors may also be contributing.


Ready to Understand Why Your Progesterone Is Low?

If you've been told your progesterone is low, or you're experiencing irregular cycles, spotting before your period, recurrent pregnancy loss, difficulty conceiving, or symptoms of perimenopause, a comprehensive evaluation can help uncover the underlying cause.


At Vital Fertility, I use a biology-first approach that looks beyond a single hormone. Through comprehensive laboratory testing and personalized interpretation, we evaluate ovulation, thyroid health, metabolic function, inflammation, nutrient status, and other key factors that influence hormone production.


Explore the Fertility Foundations Lab Panel to gain a clearer understanding of your reproductive health, or schedule a Clarity Call to discuss the best next step for your unique situation.


References

Practice Committee of the American Society for Reproductive Medicine. Diagnosis and treatment of luteal phase deficiency: a committee opinion. Fertility and Sterility. 2021.

American College of Obstetricians and Gynecologists (ACOG). The Menopause Years.

Prior JC. Progesterone for Symptomatic Perimenopause. Endocrine. 2018.

Fritz MA, Speroff L. Clinical Gynecologic Endocrinology and Infertility. 9th ed.

Barbieri RL. Physiology of the menstrual cycle. UpToDate.

Cleveland Clinic. Progesterone: Function, Levels & Symptoms.

Santoro N, Randolph JF. Reproductive aging and the menopause transition. Obstetrics & Gynecology. 2011.

National Institute for Health and Care Excellence (NICE). Menopause: Diagnosis and Management.

Reed BG, Carr BR. The Normal Menstrual Cycle and the Control of Ovulation. In: Endotext. NCBI Bookshelf.

Brinton RD, Henderson VW, Maki PM, et al. The role of progesterone in brain health and cognition across the female lifespan. Neurobiology of Aging. 2025. doi:10.1016/j.neurobiolaging.2024.12.010. PMID: 39515587.