5 Things Women With PCOS Should Know About Hypothryoidism

Thyroid disorders and polycystic ovary syndrome (PCOS) are two of the most common (and perhaps overlooked) endocrine disorders in women. Although hypothyroidism and PCOS are very different, they share many similar features. Here are five important things people with PCOS should know about hypothyroidism.

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Hypothyroidism Is Very Common in PCOS

Hypothyroidism, and in particular, Hashimoto's thyroiditis, is more common in people with PCOS than in the general population. Hashimoto's is an autoimmune condition in which the body is attacking itself.

A 2013 study found that 22.5% of women with PCOS had hypothyroidism compared to 8.75% in controls and thyroid antibodies have been shown to be present in 27% of patients with PCOS versus 8% in controls.

A 2015 study demonstrated a higher prevalence of Hashimoto's and elevated thyroid-stimulating hormone (TSH), indicating hypothyroid, in PCOS patients.

Thyroid and PCOS Are Interconnected

Both genetic and environmental factors are believed to be contributing to thyroid disorders in PCOS. Hypothyroidism is known to cause PCOS-like ovaries and overall worsening of PCOS and insulin resistance.

Hypothyroidism can increase testosterone by decreasing the level of sex hormone binding globulin (SHBG), increasing the conversion of androstenedione to testosterone and estradiol, and reducing the metabolic clearance of androstenedione.

An increased estrogen and estrogen/progesterone ratio seem to be directly involved in high thyroid antibody levels in PCOS patients.

The Thyroid Affects Your Whole Body

Located in the base of your throat with a butterfly shape, the thyroid gland regulates the rate at which your body converts food for energy, functioning as a thermostat to control the body’s metabolism and other systems.

If working too fast (hyperthyroid) it tends to speed up your metabolism. If it works too slowly (hypothyroid) this tends to slow down your metabolism, resulting in weight gain or difficulties losing weight.

All cells in your body rely on the hormones secreted by your thyroid to function properly. In addition to controlling the rate at which your body converts carbohydrates, protein, and fats into fuel, thyroid hormones also control your heart rate and can affect your menstrual cycle, affecting fertility.

TSH Testing Alone Is Not Enough

TSH alone is not a reliable test to determine your thyroid functioning. TSH measures how much T4 the thyroid is being asked to make. An abnormally high TSH test may mean you have hypothyroidism.

Relying on TSH alone is not sufficient to make an accurate diagnosis and one reason why so many people with hypothyroid are misdiagnosed. Other thyroid tests include:

  • T4 tests (free T4, free T4 index, total T4): assess the amount of T4 your thyroid is producing.
  • Anti-TPO checks for thyroid peroxidase antibody to detect autoimmune thyroid conditions like Hashimoto’s.
  • Anti-TP0
  • T3 and reverse T3 (rT3) assess the amount of T3 your thyroid is producing and its ability to convert T4 to T3.

Iodine Plays a Big Role

The thyroid must have iodine to make thyroid hormone. The main food sources of iodine include dairy products, chicken, beef, pork, fish, and iodized salt. Pink Himalayan and sea salt are not rich sources of iodine.

Keeping thyroid hormone production in balance requires the right amount of iodine. Too little or too much iodine can cause or worsen hypothyroidism. However, iodine deficiency is uncommon in the United States and iodine supplements are very rarely recommended. In cases where they are recommended, they should only be used under strict supervision of a healthcare provider.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. American Thyroid Association. Hypothyroidism: A booklet for patients and their families.

  3. Sinha U, Sinharay K, Saha S, Longkumer TA, Baul SN, Pal SK. Thyroid disorders in polycystic ovarian syndrome subjects: A tertiary hospital-based cross-sectional study from Eastern India. Indian J Endocrinol Metab. 2013;17(2):304-9. doi:10.4103/2230-8210.109714

  4. Arduc A, Aycicek Dogan B, Bilmez S, Imga Nasiroglu N, Tuna MM, Isik S, Berker D, Guler S. High prevalence of Hashimoto's thyroiditis in patients with polycystic ovary syndrome: does the imbalance between estradiol and progesterone play a role? Endocr Res. 2015;40(4):204-10. doi:10.3109/07435800.2015.1015730

  5. Mueller A, Schöfl C, Dittrich R, Cupisti S, Oppelt PG, Schild RL, Beckmann MW, Häberle L. Thyroid-stimulating hormone is associated with insulin resistance independently of body mass index and age in women with polycystic ovary syndrome. Hum Reprod. 2009;24(11):2924-30. doi:10.1093/humrep/dep285

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