Progesterone & Thyroid: A Hormonal Connection Essential for Optimal Women’s Health

Estrogen dominance. Have you heard of this? Our thyroid and sex hormones play a synchronized dance with one another and it’s no surprise that when one is off, it throws the rest off too.

Written by Steven F. Hotze, MD

When your car runs out of gas, you have to fill up the tank or it simply won’t run. Right. The same is true for women. Usually in their mid-thirties, women’s progesterone levels begin to fall more quickly than their estrogen levels, creating what we call “estrogen dominance”. If left uncorrected, this imbalance of progesterone and estrogen progressively worsens over time and many undesirable side effects can appear including premenstrual headaches, often migraine in nature, fluid retention, fibrocystic breast disease, uterine fibroids, menorrhagia (heavy, painful menstrual periods), endometriosis and functional hypothyroidism. Additionally, the incidence of breast cancer increases when women become estrogen dominant.

Physicians often tell women that if they have had a hysterectomy, they do not need to supplement with progesterone, only with estrogen. This is a big oversight, since progesterone balances estrogen. Estrogen that is not balanced with progesterone, you got that right it’s estrogen dominance, can lead to a host of health problems.

Estrogen dominance causes the liver to produce high levels of a protein called “thyroid binding globulin”, which, as its name suggests, binds the thyroid hormone and decreases the amount of thyroid hormone that can be assimilated into and utilized by the cells.

What does this lead to? Low thyroid function and all of the negative side effects that come along with it.

Estrogen and Progesterone In Harmony

Two of the most important and influential hormones in a woman’s body are estrogen and progesterone.

Estrogen is primarily produced by the ovaries and is responsible for the growth of the uterine lining during the first half of a woman’s menstrual cycle. Progesterone is also produced by the ovaries and its primary role is to prepare the uterus to receive life. Both are present throughout the menstrual cycle in different degrees. In a normal cycle, estrogen dominates the first half, and progesterone the second.

When in proper balance, these hormones aid fertility as well as mood. It’s a delicate balance, and one that can naturally be put out of balance by the experiences in a woman’s life.

Imbalance After Childbirth

During a woman’s regular menstrual cycles, progesterone is produced primarily in the ovaries. However, in pregnancy, progesterone comes from the baby’s placenta. It produces progesterone at levels much higher than the ovaries. After it’s expelled in childbirth, the body no longer has that source of progesterone. In addition, the ovaries have “turned off” for the last several months of pregnancy, and now have to turn back on and start producing progesterone again. If they don’t do this quickly or efficiently, the result is low progesterone in comparison to estrogen, a condition, as I’ve said above, called estrogen dominance.

This can be a problem in women after childbirth because it can lead to “baby blues”. Progesterone in the right amounts and in the right balance elevates the mood, so when it’s out of balance, mood suffers and depression, anxiety, and panic attacks can ensue. Other symptoms of estrogen dominance include breast tenderness, fluid retention, headaches, and severe menstrual cramps with clotting.

Furthermore, estrogen dominance is related to other hormone issues, including hypothyroidism and adrenal fatigue. All combined, these hormones are responsible for mood and energy levels, which are adversely affected with estrogen dominance.

The solution I’ve prescribed in the past with success to many patients – including my own five daughters – is to start taking bioidentical progesterone beginning the morning after giving birth. I’ve seen that this simple preventative measure helps stave off fatigue and postpartum depression.

Birth Control Pills

Oral contraceptives are another common cause of estrogen dominance, because they work by suppressing ovulation and ovarian function. A woman who is not ovulating produces no progesterone in her ovaries.

Estrogen Dominance After Menopause

Childbirth is a time of big changes in hormones in a woman’s life; menopause is another. As we age, hormones decline. Rather than decline at the same rate, though, estrogen and progesterone decline at different rates. Progesterone levels fall more quickly than estrogen, leading to – that’s right – estrogen dominance.

One reason estrogen dominates progesterone is that the ovaries aren’t the sole source of it in the body. Fat cells also produce estrogen. This means that women who are overweight or obese will produce more estrogen and may experience the effects of estrogen dominance even more compared to women who aren’t.

Another factor contributing to estrogen dominance is the presence of xenoestrogens in our bodies. Xenoestrogens are found in petrochemical products such as plastics, herbicides, pesticides, soaps, clothing, industrial by-products, and countless other manufactured goods. Xenoestrogens, “xenophobic” means alien, can cause estrogenic effects even in doses on the level of a billionth of a gram, and because they are stored in the fat cells of our bodies, most of us carry a significant burden of these toxic chemicals.

The answer to estrogen dominance during and after menopause that I favor is bioidentical progesterone to get the hormones back into balance with each other.

10 Reasons Why You Can’t Live Without Progesterone

1. Fertility/Pregnancy

Progesterone promotes survival of the embryo and fetus throughout pregnancy. It is important for the process of normal embryo implantation and early embryonic growth and development.(1,3) Progesterone deficiency can lead to miscarriage.(3) Luteal phase deficiency in natural cycles is a cause of infertility and pregnancy loss.(2)

2. PMS

Progesterone relieves the symptoms of premenstrual syndrome and regulates the menstrual cycle. Research shows that progesterone therapy for PMS resulted in much lower depression, irritability, anxiety, mood swings, abdominal bloating, sleeplessness, and breast tenderness during progesterone treatment.(4)

3. Cancer Prevention

Progesterone protects against endometrial and breast cancer. The conclusion of the 1981 Johns Hopkins study found that infertile women with progesterone deficiency had a premenopausal breast cancer risk that was 540% greater than that of women whose infertility was not related to their hormone status. Not only that, but these women had a 1,000% greater risk of death from all types of cancer. (5) Research shows that progesterone suppressed the cells from spreading and induced cell death in malignant mesothelioma cancer cells (6) and that it also can inhibit growth and cause cell death in breast cancer cells.(7)

4. Thyroid Function

Progesterone promotes assimilation of thyroid hormone into the cells, which allows your thyroid to work properly and give you energy. Research concluded that progesterone therapy increases free thyroxine (T4).(8)

5. Bone Health

Progesterone promotes bone building. Research found progesterone to be extraordinarily effective in reversing osteoporosis.(9, 10) There is evidence that progesterone may prevent and treat women’s osteoporosis. Progesterone stimulates osteoblasts and prevents bone loss in pre- and possibly perimenopausal women. Studies indicate that progesterone – likely working through bone formation pathways -plays an active role in maintaining women’s bone and in osteoporosis prevention.(11) Research shows that transdermal progesterone had bone-sparing effects.(12)

6. Sleep

Progesterone has a calming effect that helps promote sound sleep. Research shows that estrogen plus progesterone was more effective than estrogen alone in decreasing the prevalence of periodic limb movement, hot flashes, and grinding of the teeth at night, or sleepiness and attention difficulty during the day. The prevalence of breathing irregularities, arousal from sleep, anxiety, and memory impairment were decreased in both groups following progesterone treatment.(13) Studies show that decreases in progesterone levels can cause disturbed sleep. Progesterone has both sedative and anti-anxiety effects, stimulating benzodiazipine receptors, which play an important role in sleep cycle. Decrease in progesterone in postmenopausal woman is one of the causative factors of sleep apnea. Repetitive sleep induced collapse of the pharyngeal airway could happen so the postmenopausal women have higher frequency of apnea than premenopausal women.(14)

7. Fluid Retention/Weight Gain

Progesterone relieves fluid retention caused by an imbalance of estrogen and progesterone. Research demonstrates that female obesity is linked to deficient progesterone secretion.(15) A higher body weight was associated with a lower progesterone level, even in ovulatory women.(16)

8. Brain Healing

Did you know that progesterone is found in brain cells at levels twenty times higher than in the blood serum? Progesterone is a key component of the myelin sheath, the protective layer that insulates each nerve fiber. Progesterone reduces swelling and improves mental clarity after a traumatic brain injury. Estrogen and progesterone are now being studied as neuroprotective and neuroregenerative agents in stroke and traumatic brain injuries. Collectively, the hormones reduce the consequences of the injury cascade by enhancing anti-oxidant mechanisms and reducing excitotoxicity. Progesterone appears to be helpful in the post-injury treatment of both male and female subjects with acute traumatic brain damage.(17) Estrogen and progesterone treatments improve memory retention.(18)

9. Moods, Anxiety, and Depression

Progesterone acts as a natural antidepressant, enhances mood and relieves anxiety. It also relieves postpartum depression, which is caused by the drastic drop in progesterone after childbirth. Research shows that progesterone showed a significant improvement in symptoms relating to tension, mood swings, irritability, and anxiety, and confirms the alleviation of some PMS symptoms relating to anxiety and irritability with progesterone.(19) Previous studies have shown that progesterone treatment in ovariectomized rats produces an anti-anxiety response similar to that observed after the administration of benzodiazepine compounds.(20) Progesterone produces a clear dose-dependent anti-anxiety response. These results demonstrate that progesterone shows the highest anti-anxiety potency when compared with all steroids evaluated (21)

10. Migraines and Headaches

Progesterone relieves headaches and migraines. Migraine headache is more severe, disabling, and frequent during the menstrual intervals of the female reproductive cycle. Progesterone may play a role in modulating migraine headaches during luteal intervals of the menstrual cycle.(22) A high percentage of migraines in women is closely related to the menstrual cycle either at the time of ovulation or in the perimenstrual period. It can be assumed that rapid serum fluctuations due to the decline of estrogens and or progesterone trigger this type of headache. Hormonal treatment seems to be useful in order to avoid migraines.(23)

Symptoms of Estrogen Dominance

Symptoms of estrogen dominance range from mildly annoying to severe. When a woman consults a physician for help with these symptoms, she is generally given two options: surgery, usually a hysterectomy, or prescription drugs, most often counterfeit synthetic hormones that actually worsen the problem. Rarely is she told that her problem is likely the result of estrogen dominance and that natural, bioidentical progesterone could alleviate her symptoms.

• Severe menstrual cramps
• Heavy periods with clotting
• Irregular menstrual cycles
• Uterine fibroids
• Ovarian cysts
• Endometriosis
• Infertility
• Multiple miscarriages
• Fibrocystic breast disease
• Premenstrual breast tenderness
• Premenstrual fluid retention and weight gain
• Anxiety, panic attacks, or depression
• Premenstrual mood swings
• Premenstrual headaches
• Migraines
• Decreased libido

Bioidentical vs Synthetic Progesterone

If you are experiencing any of the symptoms listed above, speak to your doctor about testing your sex hormones, including progesterone. These symptoms are signs that you may need to “fill up your tank” by replenishing with progesterone in order to maintain optimal health, wellness and thyroid function. I favor natural, bioidentical progesterone. Bioidentical hormones are biologically identical in structure to the hormones produced by the human body, so a woman’s cells respond to them in exactly the same way that they respond to the hormones produced by her own body.

You should be aware that most conventional doctors will prescribe the synthetic hormone Provera for your symptoms. It is medroxyprogesterone, or progestin, a chemical that is foreign to the human body. The molecular structure of synthetic hormones has been changed in order to make them patentable for the pharmaceutical companies. They’re foreign chemicals that come with a host of possible side effects, including possible increase in risk of heart disease, strokes, blood clots, dementia, lung cancer, colorectal cancer, endometrial cancer, ovarian cancer, skin cancer, and breast cancer.(24-47)

Estrogen Dominance & The Thyroid Gland

Even if you are already taking a natural thyroid hormone for hypothyroidism, you may not be resolving an underlying cause of low thyroid function – estrogen dominance. By taking natural bio-identical progesterone along with natural desiccated thyroid, you can eliminate estrogen dominance, which will help promote proper assimilation and utilization of thyroid hormone. Given the intricate connection between thyroid and sex hormones, your sex hormones should be tested to determine if estrogen dominance is an issue for you.

In addition to dessicated thyroid and natural progesterone cream, speak to your doctor about these two supplements that are essential for optimal thyroid function and overall health:

Selenium – Selenium helps convert T4, the inactive form of thyroid, to T3, the active form of thyroid.

Vitamin D – Vitamin D is foundational for overall health, supporting the heart, immune system, bones, and moods.

While these symptoms may be common, they are not normal. If you suffer from any of these problems, you owe it to yourself to find a doctor who is experienced in treating female hormonal imbalances with natural, bioidentical hormones.

About Steven F. Hotze, M.D.

Dr. Steven Hotze is Founder and CEO of the Hotze Health & Wellness Center in Houston, Texas.

READ NEXT: A Balancing Act Between Your Adrenals, Thyroid & Sex Hormones

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