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PCOS, Hashimoto’s, Hypothyroidism, and Maximizing Your Fertility

Learn about the connection between PCOS, autoimmune Hashimoto’s thyroiditis, and an underactive thyroid.
PCOS, Hashimoto’s, Hypothyroidism, and Maximizing Your Fertility
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Polycystic Ovary Syndrome (PCOS), Hashimoto’s thyroiditis, and hypothyroidism are among the most common endocrine disorders that affect women. These hormonal conditions have many shared symptoms and can lead to other health complications. Ahead, an in-depth Q&A covering PCOS symptoms, diagnosis, and treatment, the crossover relationship among PCOS, autoimmune Hashimoto’s, and an underactive thyroid, and how PCOS/thyroid sufferers can improve fertility.

What is Polycystic Ovary Syndrome (PCOS)?

Polycystic ovary syndrome (PCOS) is a hormonal disorder estimated to affect up to 12% of women of reproductive age.

While the exact cause of PCOS is unknown, factors that likely play a role include insulin resistance, genetics/heredity, and an excess of androgenic (male) hormones. There’s disagreement among experts, but some consider PCOS to be an autoimmune disease.

Specifically, PCOS is characterized by irregular menstrual cycles – typically multiple ovulations in one cycle or no ovulation, hyperandrogenism (high levels of testosterone and other androgenic hormones), and insulin resistance.

What are the signs and symptoms of PCOS?

Symptoms of PCOS can vary from woman to woman and trigger varying levels of metabolic or menstrual irregularities. The following are the most common signs and symptoms of PCOS:

  • Menstrual irregularities including a lack of menstrual periods (amenorrhea), frequently missed/irregular periods (oligomenorrhea), very heavy periods, and anovulatory periods, where you don’t ovulate but still have menstrual bleeding.
  • Ovarian cysts, symptomatic or asymptomatic
  • Excess growth of body hair (hirsutism), especially on the face, chest, belly, or upper thighs
  • Acne (often late-onset) that responds poorly to traditional acne treatments
  • Weight gain, especially around the belly, and difficulty losing weight

Women with PCOS may also experience the following:

Not all women with PCOS experience every symptom at the same degree of severity.

PCOS can also lead to other serious health conditions, including metabolic syndrome, prediabetes, type 2 diabetes, high blood pressure, and cardiovascular disease. 

How is PCOS diagnosed?

There is no single, definitive test for PCOS. Instead, PCOS is diagnosed through physical exams, blood tests, ultrasounds, and observations of signs and symptoms.

To receive a diagnosis of PCOS, you must meet at least two of the following three criteria:

  1. irregular periods (self-reported by the patient), irregular ovulation (can be confirmed by ovulation tests)
  2. signs of increased androgens (acne, hair loss, oily skin) or tests confirming increased androgen levels (blood tests)
  3. multiple small cysts on the ovaries (typically diagnosed by transvaginal ultrasound showing an unusually high number of follicles or immature eggs)

Additional testing may include the evaluation of blood sugar levels, with tests such as fasting plasma glucose (FPG) and Hemoglobin A1C.

How is PCOS treated?

Treatment for PCOS typically requires parallel treatment approaches for the different symptoms and manifestations of the syndrome. The most effective treatments typically include a combination of the following:

  • Lifestyle changes, such as losing weight and exercising regularly
  • Dietary changes to help manage PCOS-related insulin resistance include avoiding refined carbohydrates, fried foods, sugary beverages, processed meats, and solid fats and increasing dietary fiber.
  • Medications to regulate ovulation and female reproductive hormones, such as oral contraceptives, and clomiphene and letrozole for ovulation induction
  • Medications to reduce androgens and reduce excess hair growth, such as spironolactone and eflornithine
  • Medications to improve insulin resistance and lower blood sugar, such as metformin, acarbose, and rosiglitazone
  • Treatments to control and reduce acne breakouts

It’s also important to note that undiagnosed or poorly treated hypothyroidism can worsen the symptoms of PCOS. Thyroid hormone replacement treatment for hypothyroidism should be incorporated into PCOS treatment when an underactive thyroid is diagnosed alongside the PCOS.

What’s the risk for patients with PCOS, Hashimoto’s, and hypothyroidism?

PCOS, autoimmune thyroiditis, and hypothyroidism share some common signs and symptoms, including menstrual irregularities, ovarian cysts, insulin resistance, inflammation, fertility issues, and high body mass index (BMI). But does the connection go beyond symptoms? Are patients with one condition at higher risk for the other?

The answer is unequivocal: Yes.

We don’t have any definitive studies on the likelihood of having PCOS if diagnosed with Hashimoto’s thyroiditis. However, experts have found that there is a three-fold higher likelihood of having Hashimoto’s thyroiditis in women who have been diagnosed with PCOS.

A 2015 study from the National Institutes of Health reported that 22.1% of women with PCOS had Hashimoto’s thyroiditis -- compared to only 5% of women who don’t have PCOS. These PCOS patients had high levels of thyroid peroxidase antibodies (TPOAb) and anti-Thyroglobulin antibodies (TgAb), hallmarks of Hashimoto’s thyroiditis.

One study found that, compared to a control group, women with PCOS have a much higher prevalence of goiter (27.5% vs. 7.5%) and subclinical hypothyroidism (22.5% vs. 8.75%).

Another study conducted among young women with PCOS found the prevalence of subclinical hypothyroidism (defined as TSH > 4.5 μIU/ml) to be 11.3%.

Overall, there is a demonstrably higher prevalence of thyroid disorders in women with PCOS compared to the general population. Women with thyroid disorders are also at greater risk of developing PCOS.

What links PCOS, Hashimoto’s, and hypothyroidism?

Estrogen exposure is a key factor in the link between PCOS and thyroid disease. The thymus gland is involved in regulating and preventing an autoimmune response. High estrogen exposure before birth can impair the function of the thymus, which can trigger the development of autoimmune diseases.

Estrogen levels are also implicated in autoimmune diseases, given that autoimmune conditions often start when sex hormone levels rise in our body for the first time during puberty and flare up during periods of hormonal shifts, such as during pregnancy, post-partum, and in perimenopause and menopause.

An increased estrogen-to-progesterone ratio, common in PCOS patients, causes an autoimmune response and a rise in thyroid antibody levels. Research has also shown that transient and reversible changes in the level of autoimmune response and antibody levels even happen in non-PCOS people during distinct phases of the menstrual cycle, such as ovulation.

However, in the case of high and prolonged estrogen exposure, as seen in PCOS, studies have shown that the chance of developing an autoimmune disease increases significantly.

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Research has also found that vitamin D deficiency can also trigger or exacerbate autoimmune responses. To affect different cells and tissues in our body, vitamin D needs a functional vitamin D receptor (VDR). A non-functional VDR is making people more likely to develop Hashimoto’s

Vitamin D supplementation can sometimes improve the menstrual cycle and metabolic disturbances in women with PCOS. Still, this will likely help only women with a functional vitamin D receptor.

Other levels you should consider having evaluated when you have Hashimoto’s, hypothyroidism, and PCOs include the following:

Prolactin: Hashimoto’s thyroiditis and its resulting hypothyroidism are associated with elevated levels of the hormone prolactin, also known as the breastfeeding hormone. Prolactin tends to block ovulation and can trigger the development of more ovarian cysts due to an increase in immature follicles. Prolactin levels can also be elevated in PCOS.

LH/FSH: A high ratio of luteinizing hormone (LH) to follicle-stimulating hormone (FSH) is common in both Hashimoto’s and PCOS. The LH/FSH ratio measurement may help identify PCOS in thyroid patients.

PCOS and thyroid issues together: What else can you do?

Clearly, it’s crucial to ensure that you are receiving optimal treatment for both PCOS and your autoimmune and/or underactive thyroid condition, as described above. A few additional notes:

Metformin, the type 2 diabetes medicine that helps control blood sugar levels and combat insulin resistance, is frequently prescribed to patients with PCOS. One study found six months of metformin treatment in patients with both PCOS and Hashimoto’s patients normalized TSH values, but didn’t significantly affect free T3 and free T4 levels. More research is needed, but metformin may eventually prove to be a valuable treatment for its thyroid benefits and its treatment for PCOS and insulin resistance.

Myo-inositol is a supplement that may be helpful for insulin-resistant PCOS and for Hashimoto’s and hypothyroidism patients. It’s been shown to be as effective as drugs like metformin, and it also comes with little to no side effects for most people.

You may also want to limit your intake of phytoestrogens like soy or flax seeds, as they may worsen both PCOS and hypothyroidism when overconsumed.

What about your fertility?

Polycystic ovary syndrome (PCOS) is one of the most common causes of infertility in women. PCOS affects fertility by interfering with the growth and release of eggs from the ovaries, which can prevent ovulation, a necessary step in conception. Women with PCOS may also take longer to fall pregnant than other women due to irregular periods.

According to research, insulin resistance, which can occur independently of obesity in PCOS, may also affect ovulation and fertility.

Also, while polycystic ovaries contain follicles with eggs, they frequently do not develop and mature properly, which can also lead to infertility.

If you have both PCOS and Hashimoto’s/hypothyroidism, don’t give up on the idea of having a baby, because it’s possible! You may, however, need more oversight, guidance, and adjustment to create the right circumstances for conception and healthy pregnancy.

For women with both PCOS and thyroid conditions, the first step is to optimally treat your thyroid problem. That involves optimizing your thyroid hormone replacement treatment and achieving levels considered ideal for fertility.

In some cases, thyroid treatment may normalize ovulation, but if that’s not confirmed, the next step is to ensure that you’re consistently ovulating. You may benefit from keeping track of your Basal Body Temperature (BBT), monitoring fertility signs, and using an ovulation predictor kit to establish regular ovulation. Consider using a fertility tracking app like Natural Cycles, Clue Period Tracker & Calendar, or Fertility Friend. You can also get the Oova Fertility Tracking system, which includes ovulation tests and a tracking app. Finally, you can also download a more old-school but highly effective BBT/Fertility Chart at OvaGraph.

If you’re not ovulating consistently and on schedule, your healthcare provider or fertility specialist can work with you on medical treatments to help regulate and promote consistent ovulation. The drug clomiphene, for example, has been shown to increase the chance of getting pregnant by six times in women with PCOS compared to those who don’t take this medication.

You should also be aware that low progesterone levels are common in both PCOS and Hashimoto’s. Low levels of progesterone can lead to implantation difficulties after an egg is fertilized, triggering an early miscarriage. As part of a pre-conception/fertility evaluation, you should consider testing progesterone levels to determine if you should supplement with progesterone after ovulation to enhance successful implantation.

Women with PCOS who don’t respond to medications the first-line medications may be prescribed gonadotropins and hCG.

Finally, if these approaches aren’t effective, don’t give up! Assisted reproduction technologies (ART) like intrauterine insemination (IUI) and in-vitro fertilization (IVF) may help increase your chance of a successful pregnancy with PCOS and thyroid conditions!

An important note: In vitro maturation (IVM) is a less-known treatment option for women with PCOS who need assisted reproductive technology. IVM involves surgically harvesting eggs before they are matured. Unlike IVF, which collects mature eggs, IVM uses a low dose of gonadotropins – or no medication. One meta-analysis of 11 trials indicates that IVM is effective for women with PCOS in terms of pregnancy and live birth rates. Clinical pregnancy and implantation rates obtained from IVM treatment in infertile women with PCOS are approximately 30-35% and 10-15%, respectively. IVM is also considered the best ART option for women with PCOS who also need to manage a condition known as ovarian hyperstimulation syndrome, which is a known risk for women with PCOS.

A note from Paloma

The most important takeaway is this: Experts agree that if you have PCOS, you should be screened for thyroid disorders. And if you have Hashimoto’s and/or hypothyroidism, you should be screened for PCOS – especially if you are planning to conceive or having fertility problems.

Paloma Health can play an essential role by ensuring comprehensive testing, diagnosis, and management of your Hashimoto’s thyroiditis and hypothyroidism. Paloma’s top thyroid practitioners can work with you pre-conception to help ensure optimal thyroid function for fertility and a healthy pregnancy. Learn more about scheduling a virtual appointment with a Paloma provider now.

You can also make regular thyroid testing easy and convenient with Paloma’s home thyroid test kit. While many labs only look at Thyroid Stimulating Hormone (TSH) to assess thyroid function, Paloma believes it is also critical to measure Free Triiodothyronine (Free T3), Free Thyroxine (Free T4), and Thyroid Peroxidase antibodies (TPOAb). That’s why the easy-to-use home test kit tests for all four key thyroid values, with the option to add on Vitamin D and Reverse T3 tests.

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Finally, three diets that may aid those with PCOS in managing their symptoms are:

1.     A low glycemic index (GI) diet, whereby the body digests foods with a low GI more slowly, meaning they do not cause a rapid spike in blood sugar

2.     A diet rich in natural, unprocessed foods, high-fiber foods, and fatty fish, including salmon, tuna, sardines, and mackerel

3.     A diet that avoids foods that can ramp up inflammation, such as fried foods, saturated fats, red meat, processed snacks, and full-fat dairy.

Our Paloma nutritionists can work with you to finetune your diet for optimal thyroid health and improve PCOS-related insulin resistance.

Paloma Health’s Director of Research Vedrana Högqvist Tabor, PhD contributed to this article


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Diamanti-Kandarakis E, Kouli CR, Bergiele AT, Filandra FA, Tsianateli TC, Spina GG, Zapanti ED, Bartzis MI. A survey of the polycystic ovary syndrome in the Greek island of Lesbos: hormonal and metabolic profile. J Clin Endocrinol Metab. 1999 Nov;84(11):4006-11. doi: 10.1210/jcem.84.11.6148. PMID: 10566641.

Dunaif A. Insulin resistance and the polycystic ovary syndrome: mechanism and implications for pathogenesis. Endocr Rev. 1997 Dec;18(6):774-800. doi: 10.1210/edrv.18.6.0318. PMID: 9408743.

What are the symptoms of PCOS? Published January 31, 2017.

How do health care providers diagnose PCOS? Published January 31, 2017.

Diagnosing Polycystic Ovary Syndrome.

Radosh L. Drug Treatments for Polycystic Ovary Syndrome. American Family Physician. 2009;79(8):671-676.

Polycystic Ovarian Syndrome Medication: Hypoglycemic Agents, Antiandrogens, Topical Hair-Removal Agents, Oral Contraceptives, Selective Estrogen Receptor Modulators, Acne Agents, Topical.

Hashimoto’s Thyroiditis and PCOS: Is There a Connection? EndocrineWeb.

Ayse Arduc, Bercem Aycicek Dogan, Sevgi Bilmez, Narin Imga Nasiroglu, Mazhar Muslum Tuna, Serhat Isik, Dilek Berker & Serdar Guler (2015) High prevalence of Hashimoto’s thyroiditis in patients with polycystic ovary syndrome: does the imbalance between estradiol and progesterone play a role?, Endocrine Research, 40:4, 204-210, DOI: 10.3109/07435800.2015.1015730.

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Mary Shomon

Patient Advocate

Mary Shomon is an internationally-recognized writer, award-winning patient advocate, health coach, and activist, and the New York Times bestselling author of 15 books on health and wellness, including the Thyroid Diet Revolution and Living Well With Hypothyroidism. On social media, Mary empowers and informs a community of more than a quarter million patients who have thyroid and hormonal health challenges.

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