But why is this fact so important when you are trying to get pregnant?
The Thyroid gland is known as the “Master Controller” as it controls your whole metabolism (how your body breaks down food and converts it into energy), brain and digestive function, blood pressure and even how fast your heart beats. In fact every cell in your body requires Thyroid hormone in order to function.
Certain prescription medications such as cholesterol lowering drugs and steroids can block Thyroid function but something as simple as a mineral deficiency also plays a major role in Thyroid health. A deficiency of the mineral Iodine for example can lower Thyroid function because Iodine is essential to produce Thyroid hormone.
Two of the most important female hormones are Oestrogen and Progesterone which need to be in balance for optimal fertility. If Progesterone levels fall, Oestrogen levels rise creating an imbalance called Oestrogen dominance. One of the main problems with oestrogen dominance is it causes the liver to produce what is called TBG (Thyroid Binding Globulin) which prevents Thyroid hormone from being utilised properly in each of your cells. This invariably leads to low Thyroid function.
Blood tests which only measure the amount of TSH (Thyroid Stimulating Hormone) you are producing is really an incomplete blood test, and may be interpreted by your GP as ‘normal’. If the blood test does not also test your levels of T4 as well as T3 (which is the active form of Thyroid hormone), you don’t truly know the whole picture.
When interpreting a Thyroid function blood test, what does the TSH level actually tell us? If you have insufficient T4 and T3, the TSH result will be high. Conversely your TSH level will be low if you have an excess of T4 and T3. Let’s not forget the amount of hormone actually being assimilated into each of your cells can be abnormal due to the presence of Thyroid Binding Globulin (TBG). You may not be efficiently converting inactive T4 into the active T3 form. Therefore a thorough Thyroid function test would check your levels of TSH, T4, T3, reverse T3 and autoantibodies (autoimmune disease indicator).
Hence women suffering from Oestrogen dominance may be exhibiting symptoms of Hypothyroidism (low functioning Thyroid) only to be told that everything looks ‘normal’ on their Thyroid test. Sound familiar? This is why an under functioning Thyroid can have a significant impact on your ability to conceive.
Some of the symptoms of low Thyroid function may include skipped or irregular periods, clotting and heavy bleeding, unexplained weight gain or difficulty losing weight (even if exercising and consuming a healthy diet), and fatigue. This is by no means a comprehensive list of symptoms and of course could be contributed to a myriad of other health conditions – however around 25% of women who have been previously diagnosed with unexplained infertility may have Hypothyroidism (low Thyroid hormone synthesis). Hypothyroidism can reduce the levels of Luteinising hormone (LH) and Follicle Stimulating Hormone (FSH) which are essential for the maturation of egg follicles as well as your ovaries’ production of Oestrogen and Progesterone.
It is vitally important I believe to not only check your hormone levels, but to undergo a comprehensive Thyroid function test in order to get a clear understanding of the health of your body as a whole when preparing for a healthy conception and pregnancy.
Don’t despair if you feel like you have been doing everything ‘right’ diet and lifestyle wise – there may be light at the end of the tunnel! Working with a natural health care professional such as a Naturopath who understands the link between your Thyroid, hormones and infertility can support you on your conception journey. Healing factors such as poor digestive function for instance may be affecting how well your body converts Thyroid hormones into its active and useable form. Every patient is unique and requires a multi-faceted, personalised approach to treatment using a combination of nutritional supplements, diet, mineral therapy and herbal medicines.
Your Thyroid may just be the missing piece of the conception puzzle.