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  • Writer's pictureTara Ross

The PMS Thyroid Connection

There are two scenarios involving premenstrual syndrome (PMS) and low thyroid function I commonly see in my naturopathy clinic:


A client presents with constant low mood, fatigue and brain fog that all get significantly worse in the week before her period. She is experiencing a form of PMS called premenstrual magnification, a temporary worsening of symptoms that are caused by an underlying health condition, which I suspect is undiagnosed low thyroid function. Even though her GP has already tested TSH, and it falls under the ‘normal range’, through further investigation I find that she does indeed have low thyroid function. After starting on thyroid hormone replacement she finds that her symptoms quickly improve, especially in the week before her period.


A client with diagnosed low thyroid function taking thyroid hormone replacement presents with PMS. She has excess oestrogen PMS symptoms of breast tenderness and irritability as well as the progesterone deficiency PMS symptom of premenstrual spotting. After improving oestrogen detoxification and supporting progesterone production she finds that; not only have her PMS symptoms have improved, her thyroid symptoms have also reduced and her thyroid hormones are at the best levels she has had for a long time.


This is not surprising, as low thyroid function has a significant effect on period health and vice versa. It is the reason why I always investigate thyroid health when treating PMS and why I often see an easing of low thyroid symptoms when treating PMS.


PMS is very common, even without having low thyroid function, but should not be considered ‘normal’ or untreatable. PMS responds quickly to the naturopathic treatment I will discuss in this blog post. I find my clients see results within the first menstrual cycle, I do however advise that you allow at least three months to experience the full benefits of this treatment.


How does low thyroid function affect your period health?


Low thyroid function can affect your period health in several ways. It can cause your pituitary gland to make too much of the hormone prolactin, disturb the function of the hormones FSH and LH, decrease insulin sensitivity, and deplete the cellular energy of ovarian follicles. All of which can impair or even suppress ovulation.


Ovulation is the most important phase of your menstrual cycle and is needed to produce progesterone. If you have low thyroid function you may not ovulate regularly, causing either irregular menstrual cycles that are shorter than 21 days or longer than 35 days, or periods that last longer than 7 days. These are anovulatory menstrual cycles during which you do not produce progesterone.


Even if you do have a regular monthly menstrual cycle, low thyroid function may cause you to not produce enough progesterone after ovulation. This can cause premenstrual spotting and/or heavy periods, common symptoms of both progesterone deficiency and low thyroid function.


In a healthy ovulatory cycle, your oestrogen to progesterone ratio is balanced. In the follicular phase, from the start of your period to ovulation, oestrogen levels rise to thicken your uterine lining to prepare for implantation of a fertilised egg. In the luteal phase, from ovulation until the start of your period, progesterone is produced by the corpus luteum to maintain the uterine lining and to hold a pregnancy if a fertilised egg is implanted.

If you regularly have anovulatory cycles or cycles where you do not produce enough progesterone, your oestrogen to progesterone ratio becomes imbalanced with too much oestrogen in comparison to progesterone.


In people with low thyroid function, an imbalanced oestrogen to progesterone ratio can often exacerbate menstrual symptoms, especially PMS.


What is PMS?


Common symptoms include mood changes such as irritability, ‘short fuse’, teariness, anxiety and depression. You can also experience other physical symptoms such as breast tenderness, premenstrual spotting, bloating and fluid retention, insomnia, acne, headaches or migraines, fatigue, brain fog and food cravings.


Symptoms can start as early as straight after ovulation but most often occur within 3 to 7 days before the period starts and subside during or shortly after the period finishes.


What causes PMS?


A common misunderstanding is that the female hormones oestrogen and progesterone themselves are what cause PMS, particularly mood disturbance symptoms. Oestrogen and progesterone are both actually very beneficial for mood. Oestrogen boosts the ‘feel good’ neurotransmitters, serotonin and dopamine. Progesterone boosts GABA, a calming neurotransmitter. Problems only arise when there is an imbalance of the oestrogen to progesterone ratio.


Whilst oestrogen is beneficial, excess oestrogen can cause PMS symptoms including irritability and breast tenderness. Excess oestrogen occurs when you have difficulty detoxifying and removing oestrogen from your body. Low thyroid function can impair oestrogen detoxification and the resulting excess oestrogen levels can further suppress thyroid function.


Oestrogen falls in the late luteal phase, the time when PMS symptoms are most often reported. If you have excess oestrogen, this fall can feel like going down a rollercoaster, exacerbating PMS symptoms.


Progesterone protects you against the fall of oestrogen, so you need to work on making enough during your luteal phase. The problem is that progesterone is hard to make when you have low thyroid function. You need an optimal level of thyroid hormones for healthy ovulation to then produce an optimal level of progesterone. Progesterone then helps to increase thyroid hormone production as part of a feedback loop. Low thyroid hormone levels lead to low progesterone which leads to further low thyroid hormone production.


In summary, to treat PMS you need to optimise thyroid hormone levels to ensure healthy ovulation at the same time as promoting healthy detoxification of oestrogen and maximising progesterone production.


How can I optimise my thyroid hormone levels?


Ask a naturopath or GP to test for the full panel of thyroid hormones to get a complete picture of your thyroid health. You need to ask for TSH, Free T4, Free T3, Reverse T3, and the thyroid antibodies, TPO and TG.


Interpret your own test results - you want to aim for a TSH of less than 2, for T4 to be in the top end of the reference range at around 18 – 20, and for T3 to be above 5. If your thyroid levels are suboptimal, you may benefit from a dose increase of your thyroid hormone replacement medication. If you are not taking any thyroid hormone replacement medication, you may benefit from asking your GP to start on a dose that will help to supplement the hormones that your thyroid can no longer produce in optimal amounts.


Get a second opinion if your GP will not adjust your dose or start you on thyroid hormone replacement. The Thyroid WA Facebook page has a list of thyroid savvy integrative GPs in Western Australia.


Use the signs and symptoms checklist that Thyroid WA have on their Facebook page to assist your GP in monitoring your symptoms and adjusting your thyroid hormone replacement dosage.


Treat autoimmunity if you have elevated levels of either or both thyroid antibodies, TPO and TG, as this means you have the most common cause of low thyroid function, Hashimoto’s thyroiditis. This is an autoimmune condition where your immune system accidentally attacks your thyroid gland over time. You need to treat autoimmunity in order to optimise thyroid health. Follow a gluten and diary free diet as the proteins in both trigger autoimmunity. Support gut health to repair intestinal permeability, also known as leaky gut. Leaky gut is where gaps form between the cells of your intestines. This allows proteins, such as casein from dairy and gliadin from gluten, as well as toxins to activate the immune system, which triggers and drives autoimmunity. Bone broth, collagen, and prebiotic and probiotic foods all help to repair leaky gut. Make sure you have optimal levels of the nutrients that help to reduce autoimmunity and aid thyroid function. Ask a naturopath or GP to test for Vitamin A, Vitamin D, selenium, zinc, iron, magnesium, folate and Vitamin B12 levels. Your health professional can then assist you in identifying and correcting any nutrient deficiencies.


Improve T4 to T3 ratio as many people have difficulty converting T4 into the more active form, T3. Chronic inflammation, stress, insulin resistance and/or having a genetic variant of the enzyme that converts T4 to T3 are all conditions that affect T4 to T3 conversion. Symptoms of poor T4 to T3 conversion include fatigue, low mood and brain fog. If you suspect you may have issues with T4 to T3 conversion you can support gut health as this is where most of the conversion of T4 to T3 takes place. You can also consider taking a selenium supplement or increasing your dietary intake of selenium, if blood testing shows a deficiency. Selenium reduces inflammation and oxidative stress in the thyroid gland, improves T4 to T3 conversion and reduces thyroid antibodies. The therapeutic dose is narrow though, so only take up to 150mcg of selenium daily, including through dietary sources and other supplements such as multivitamins. If your T3 levels do not improve, you can talk to your GP about taking combination thyroid hormone replacement therapy. This can either be a combination of thyroxine (T4) and T3 medication, or NDT (desiccated thyroid extract) that is derived from porcine thyroid gland and contains both T4 and T3. However, most GPs are only fluent in prescribing thyroxine, so I would recommend seeing one of the more thyroid savvy integrative GPs that Thyroid WA recommend if you wish to trial combination therapy.


How can I detoxify oestrogen more effectively?


Reduce alcohol as it significantly impairs oestrogen detoxification.


Maintain healthy intestinal bacteria as healthy bacteria increase oestrogen detoxification and clearance and unhealthy bacteria cause reabsorption of oestrogen by your body. Increase prebiotic and probiotic foods and consider taking a probiotic supplement to help maintain healthy intestinal bacteria.


Reduce exposure to xenoestrogens, such as plastics, pesticides and petrochemicals, as they affect oestrogen detoxification and hyperstimulate oestrogen receptors. Avoid heating foods up in plastic in the microwave and drinking from disposable plastic water bottles, switch to organic fruit and vegetables or thoroughly wash them before eating to avoid pesticides, and swap skin and hair products to brands that are petrochemical free.


Increase intake of phytoestrogens such as sprouts, legumes and seeds (especially flax/linseed), as they out compete your body’s excess oestrogens by binding to oestrogen receptors.


Improve healthy oestrogen metabolism by assisting liver function. Oestrogen can be metabolised into different forms by the liver. Some are more unhealthy metabolites that have been linked to increased risk of breast and other reproductive cancers. Vegetables from the brassica family – broccoli, cauliflower, Brussels sprouts, kale, bok choy, pak choy, and cabbage contain Indole-3-Carbinol (I-3-C). I-3-C increases the healthy metabolism, detoxification, and clearance of oestrogen. Aim to have at least one cup of these vegetables (lightly steamed to reduce goitrogenic effects) a day.


Improve bowel regularity as chronic constipation can reduce oestrogen detoxification and clearance. Exercise regularly, drink at least two litres of water daily, increase intake of prebiotic and probiotic foods, and increase dietary fibre (linseed meal, chia seeds, fruit and vegetables) to improve bowel transit time and regularity.


Consider having a saliva hormone test to get a full picture of your reproductive hormone health. Whilst this test is not covered under Medicare, saliva hormone testing is more accurate than standard blood testing for the reproductive hormones oestrogen, progesterone and testosterone and can also test the adrenal hormones, cortisol and DHEA. Adrenal hormones, like thyroid hormones, can also affect reproductive hormone balance. Saliva hormone testing can also assess how well you are metabolising your oestrogen. A naturopath or an integrative GP can organise a saliva hormone test for you. They can then analyse the results and develop an individualised treatment plan for you including dietary and lifestyle advice, as well as any required herbal/nutrient supplementation, to help you achieve hormone balance.

How can I maximise my progesterone production?


Reduce alcohol as it blocks progesterone’s calming effect on your brain.


Reduce inflammatory foods such as sugar, gluten and dairy, as lowering inflammation improves both ovulation and the function of your progesterone receptors, increasing progesterone production.


Reduce stress as adrenaline blocks your progesterone receptors and progesterone is used to make another stress hormone, cortisol.


Exercise as it reduces both stress and inflammation.


Consider taking magnesium as it increases progesterone production, regulates cortisol and decreases inflammation. 300mg elemental magnesium daily is a therapeutic dose. The form of magnesium you take is important. Some forms of magnesium, such as oxides and sulphates, are poorly absorbed orally and can have an osmotic laxative effect. Forms such as bisglycinates, glycinates, orotates and citrates are better tolerated. If you don’t want to take a supplement, you can have Epsom salt (magnesium sulphate) baths or use topical magnesium oils or sprays as magnesium is well absorbed through the skin also.


Consider taking a selenium supplement or increasing your dietary intake of selenium, if blood testing shows a deficiency. Selenium improves corpus luteum health to increase progesterone production as well as having the previously discussed thyroid health benefits. The therapeutic dose is narrow though, so only take up to 150mcg of selenium daily, including through dietary sources and other supplements such as multivitamins.


Consider herbal medicine – herbs that work on the hypothalamus/pituitary/ovarian (HPO) axis can improve PMS symptoms and regulate your menstrual cycle by improving ovulation, which increases progesterone production. However, they should only be taken under supervision of a naturopath or integrative GP as they can have contraindications with pregnancy, breast feeding and certain health conditions; drug/herb interactions; and specific dosage amount and duration requirements. Herbs that work on the hypothalamus/pituitary/adrenal (HPA) axis are known as adaptogenic herbs. They help to regulate cortisol production, sparing progesterone, and can have both anti-depressant and anti-anxiety effects. Once again, these herbs should only be taken under supervision of a naturopath or integrative GP as they can have contraindications with pregnancy, breastfeeding and certain health conditions; drug/herb interactions; and specific dosage amount and duration requirements.


Consider having a saliva hormone test to get a full picture of your reproductive hormone health. Whilst this test is not covered under Medicare, saliva hormone testing is more accurate than standard blood testing for the reproductive hormones oestrogen, progesterone and testosterone and can also test the adrenal hormones, cortisol and DHEA. Adrenal hormones, like thyroid hormones, can also affect reproductive hormone balance. A naturopath or an integrative GP can organise a saliva hormone test for you, analyse the results, and recommend dietary and lifestyle advice as well as any required herbal/nutrient supplementation to help you achieve hormone balance.


I hope this blog post has given you some useful tools to help you optimise your thyroid and reproductive hormone levels, so you can be rid of your PMS symptoms. As I mentioned earlier, please allow at least three months to see the full benefits of this treatment. If your symptoms persist, I would be happy to help you by identifying the cause/s of your symptoms and recommending a more individualised treatment plan for you. If you would like any further information on PMS and low thyroid function or would like to find out more about my services and how I can help you, you can contact me through the contact form on each page of this website or call me during business hours on 0432 428 947.

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