•  What is estrogen dominance?
  •  Signs and symptoms of estrogen dominance
  •  Hypothyroidism / estrogen dominance
  •  Hypothyroidism / estrogen dominance / obesity
  •  Estrogen therapy and contraception


Low thyroid is often the ignored factor in women who are treated for symptoms attributed to menopause. It is estimated that by age 50 one out of every ten/twelve women has some degree of hypothyroidism. By age 60 it is one out of every five/six. The prevalence of thyroid antibodies increases with age.
Many women confuse hypothyroidism symptoms with menopause symptoms. Insomnia, irritability, depression, palpitations and "fuzzy thinking" are common symptoms of both.
If there were symptoms of hypothyroidism prior to menopause with thyroid hormone tests in the "standard", the thyroid disease should be reconsidered and a full blood workup performed, including antibodies.

• What is Estrogen Dominance?
Estrogen and progesterone are secreted by the ovaries These two female hormones work in synchronization with each other, progesterone acting as an antagonist to estrogen, to achieve hormonal harmony. When they are off balanced, it leads to significant medical problems. While sex hormones decline with age, there is a dramatic change in the rate of decline during the pre-menopausal and menopausal years for women in these two hormones.
From age 35 to 50, there is a 75% reduction in production of progesterone in the body. Estrogen, during the same period, only declines about 35%. By menopause, the total amount of progesterone made is extremely low, while estrogen is still present in the body at about half its pre-menopausal level. This means that at menopause the ovaries cease production of progesterone before to cease production of estrogen. Estrogen dominance is caused by an excess of estrogen in relation to the amount of progesterone that is available to balance or inactivate the effects of estrogen. It is manifest especially if poorly controlled stress prevents the adrenal gland to take over to produce progesterone (Click Here).

Signs and Symptoms of Estrogen Dominanceptoms of Estrogen Dominance
They include: swollen breasts and breast tenderness, fibrocystic breasts, uterine fibroids, endometriosis, irregular menstrual periods, missing periods, increased blood clotting, PMS (premenstrual syndrome), decreased sex drive, water retention (swollen fingers and feet), bloating, fat gain (especially around the abdomen, hips and thighs), muscle cramps, constant tiredness, memory loss, mood swings, irritability, depression with anxiety, hair loss, headaches, hypoglycemia, insomnia, dry eyes, dry skin, osteoporosis, accelerating of the aging process.

We find many of the symptoms of hypothyroidism.

• Hypothyroidism/Estrogen Dominance
Hypothyroidism is more common in women, probably because the female hormones exert their effects on thyroid function. Progesterone facilitates the action of thyroid hormone, while estrogen is antagonistic to thyroid hormone. So, if a woman has low progesterone and/or a high level of estrogen, it is more difficult for the thyroid hormone to do its job. The symptoms of hypothyroidism may occur because estrogen dominance.

The type of hypothyroidism that watches for women because of hormonal interactions does not lead to a disease of the thyroid gland but to a dysfunction described as "functional hypothyroidism". Here is the description given by Dr. George Gillson, M.D., medical director of the laboratory in Calgary RMA: "Functional hypothyroidism is a very common problem that affects thousands of women in Canada. Typically, thyroid tests are normal, but are present all the symptoms of a slowdown in the gland, or hypothyroidism".

The late Dr. John R. Lee, M.D., was an international authority and pioneer in hormone balance for women and men. We owe him the expression "estrogen dominance". According to Dr. Lee, estrogen dominance is behind many cases of midlife hypothyroidism. Dr. Lee, based on his clinical experience, suggests in his works that when estrogen is not properly counterbalanced with progesterone, it can block the action of thyroid hormone, so that even when the thyroid is producing normal levels of the hormone, the hormone is rendered ineffective and the symptoms of hypothyroidism appear. In this case, laboratory tests may show normal thyroid hormone level because the thyroid gland itself is not malfunctioning. Prescribe progesterone in small quantities in the form of transdermal cream will help improve the cellular response to these hormones. Most symptoms are greatly reduced.

The problem is compounded when a woman is prescribed for her pre-menopause or menopause supplement estrogen therapy alone, since it will exacerbate all the existing hormonal imbalance (Click Here).

Thus, many pre-menopausal, menopausal or postmenopausal women with clinical signs of hypothyroidism, such as fatigue, lack of energy, intolerance to cold, are actually suffering from unrecognized estrogen dominance and will benefit from supplementation with natural progesterone.

• How does Estrogen Dominance affect the thyroid function?
Estrogens increase the synthesis of the thyroxin-bounding globulin (TBG), a carrier-protein, produced in the liver, that bounds thyroid hormone to it, making the thyroid hormone partially inactive. Only free hormones - unbound - are active. TBG excess, acting as hormones storage pool, thus increases the portion of inactive hormones at the expense of the free portion therefore less available to the tissues.
Estrogens are also known to reduce the conversion of T4 to T3, leading to a preferential conversion to reverse-T3 (inactive T3). Excess reverse-T3, blocking the receptors, such as a faulty key in a lock, slows cellular activity of all cells, causing symptoms of a hypo-active thyroid.

 • Hypothyroidism/Estrogen Dominance/Obesity
Estrogen causes food calories to be stored as fat. Thyroid hormone causes fat calories to be turned into usable energy. Thyroid hormone and estrogen therefore have opposing actions.
The dominance of estrogen in affecting thyroid receptor will be responsible for a functional hypothyroidism, which will cause weight gain by accumulation of fat around the hips, thighs and low abdomen. Note that estrogen is also present as phytoestrogens and xenoestrogens in our environment. This weight gain will be made despite any attempt to diet or exercise. Functional hypothyroidism and weight gain will not be corrected by prescribing a thyroid hormone replacement therapy, which does not take into account the underlying problem, namely estrogen dominance. Only treatment with natural progesterone will reduce the excess weight by balancing estrogen dominance and reactivating the thyroid receptors. Estrogen dominance will disappear and thyroid receptors work again fully, i.e. the hypothyroid condition will normalize. (Click Here)

• Hormone Replacement Therapy (HRT) and birth control pills
HRT at any form, in order to regulate the menstrual cycle, or for pre-menopause and menopause, or as birth control pills, is likely to create a thyroid problem.
The contraceptive pill contains synthetic estrogen and progesterone. Taking the pill will suppress the endogen production of progesterone, which does a great job of preventing a woman from becoming pregnant, but also will create chaos with the endocrine system. As a result, a progesterone deficiency can develop, leading to estrogen dominance, which not only can affect the thyroid health, but the overall health as well. One obvious solution to this is to stop taking oral contraceptives, but many women won’t want to do this, even if it is negatively affecting their health. For those women who want to remain on the pill, taking natural progesterone can help with the progesterone deficiency. Of course it’s not offering a permanent solution. However, this can help to manage the symptoms of estrogen dominance while someone is taking oral contraceptives. But as I mentioned, the ideal situation would be to stop taking oral contraceptives altogether. And the long term consequences are worse for someone who took the pill at an earlier age. (Click Here)

If contraception is prescribed for menstrual irregularity or PMS (premenstrual syndrome), it must be keep in mind that a thyroid problem can cause irregular periods and PMS, or vice versa, contraception may be responsible of a thyroid problem.

If symptoms of functional hypothyroidism appear in a woman taking HRT or birth control pills, the best treatment, in many cases, is to stop the treatment or pill and see if symptoms disappear. In case of menopause, naturel progesterone should be prescribed alone, but after consulting a gynecologist. If a thyroid hormone replacement therapy be necessary, personally I always start by prescribing T3 sustained release (I will return in the processing) and not a T4-only preparation (Elthroxine, Euthyrox, Synthroid), typically given, in an attempt to shorting failure conversion of T4 to T3.

Finally, if a patient with Hashimoto's thyroiditis is prescribed a birth control pill, she is more likely to need more thyroid hormone as estrogen contained in the pill works against it.
Autoimmune diseases including lupus and Hashimoto's thyroiditis have also been linked to estrogen dominance and other hormonal imbalances. For some women, estrogen dominance takes a serious and potentially fatal form, such as cancer of the breast or uterus. (Click Here)


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