Thyroid Dysfunction in Perimenopause
Did you know that the incidence of thyroid dysfunction increases in the menopause transition?
At this time in a woman’s life, the secretion and metabolism of thyroid hormones changes. This increases her risk of a thyroid condition.
Thyroid hormones are intimately related to our other sex hormones, especially estrogen and progesterone.
Let’s quickly talk about our thyroid hormones:
- TSH (thyroid stimulating hormone) is the hormone produced by the brain to tell the thyroid to produce more thyroid hormone. When TSH is high it generally indicates that thyroid hormones are trending low.
- T4 and T3 are the most common thyroid hormones; these are low when thyroid is under-functioning (hypo) and high when thyroid is over functioning (hyper).
- TPO is a thyroid antibody which is elevated when there is an autoimmune thyroid disorder- Hashimoto’s is autoimmune hypothyroidism and Graves is autoimmune hyperthyroidism.
How do sex hormones affect thyroid function?
- Progesterone (a hormone produced with ovulation) has been shown to improve TSH levels. Since women in perimenopause ovulate less frequently, they naturally produce less progesterone, therefore increasing TSH levels.
- Estrogen increases the production of thyroid binding globulin which binds up thyroid hormone and increasing TSH (thyroid stimulating hormone). This is important when considering estrogen replacement in the menopause transition because the estrogen may decrease T4 and increase TSH. If a woman is already on thyroid when starting HRT she may need an increase thyroid dose.
Though incidence of thyroid disorders increases in the menopause transition, especially above the age of 50, there is no consensus on screening. A problem that occurs in the menopause transition, is that, though there is an increased risk of thyroid dysfunction at this time, thyroid-related symptoms can be explained away by menopause since the symptoms can often be subtle. Therefore, clinical manifestations of thyroid disfunction that appear at this time (sometime as early as 40) including weakness, fatigue, dry skin, hot or cold intolerance, mood changes, atrial fibrillation, and weight changes, to name a few, should be investigated.
Identification and treatment of thyroid conditions in this age group is especially important because some of the effects of thyroid dysfunction are also risks of low estrogen status.
There is well-known evidence about the effect of thyroid status on cognitive function, CVD risk, bone turnover and longevity, all things that are also affected by estrogen changes in menopause.
Once a thyroid condition is identified and being treated there is also a need for closer monitoring during the menopause transition. This is because variable estrogen and progesterone levels can alter her response to the thyroid medication, resulting in periods of over or under-treatment.
Lastly, all women with premature ovarian failure (POF) should be screened for an autoimmune thyroid condition by testing her TSH and antibody testing. There is a much higher risk of Hashimoto’s in women with POF.
Decision for menopausal hormone therapy should be individualised regardless of concomitant thyroid disease. However, as mentioned above, if a woman is taking hormone replacement and has a thyroid condition, she may need an increase in her thyroid hormone once she starts on estrogen. 1,2
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Dr. Lisa Maddalena, ND
- Pearce, E. N. Thyroid dysfunction in perimenopausal and postmenopausal women. Menopause Int 13, 8–13 (2007).
- Uygur, M. M., Yoldemir, T. & Yavuz, D. G. Thyroid disease in the perimenopause and postmenopause period. Climacteric 21, 1–7 (2018).