How Your Thyroid Plays an Important Role in PCOS

PCOS | May 8, 2025 | By Jessica Silver, APRN, FNP-C

If you've been diagnosed with Polycystic Ovary Syndrome (PCOS), you're likely familiar with its common symptoms: irregular periods, excess hair growth, acne, weight gain, and fertility challenges. What you might not know is that up to 25% of women with PCOS also have thyroid dysfunction—a critical connection that conventional medicine often overlooks.

This overlooked thyroid-PCOS connection could be the missing piece in your treatment puzzle, especially if you've been following standard PCOS protocols without seeing the results you hoped for.

The Thyroid-PCOS Connection: More Common Than You Think

Research shows that women with PCOS are three times more likely to have autoimmune thyroid disease compared to women without PCOS. This connection isn't coincidental—these conditions share several underlying mechanisms and can actually worsen each other when both are present.

The most common thyroid condition affecting women with PCOS is Hashimoto's thyroiditis, an autoimmune condition where the immune system attacks the thyroid gland, leading to hypothyroidism (underactive thyroid). Even subclinical hypothyroidism—where TSH is elevated but still within the broad "normal" range—can significantly impact PCOS symptoms and treatment outcomes.

How Thyroid Dysfunction Makes PCOS Worse

When thyroid function is compromised, it can exacerbate PCOS symptoms in several ways:

1. Worsened Insulin Resistance

Hypothyroidism reduces insulin sensitivity, making insulin resistance—a core feature of many PCOS cases—even worse. This creates a vicious cycle where insulin resistance increases testosterone production, worsening PCOS symptoms.

2. Disrupted Ovulation and Menstrual Cycles

Thyroid hormones directly influence ovarian function. Even mild thyroid dysfunction can disrupt ovulation and menstrual regularity, compounding the cycle irregularities already present in PCOS.

3. Increased Inflammation

Both PCOS and thyroid autoimmunity involve inflammatory processes. When both conditions are present, inflammation increases, potentially worsening symptoms of both conditions.

4. Compromised Fertility

Thyroid dysfunction can reduce fertility beyond the challenges already posed by PCOS, making conception more difficult and increasing miscarriage risk.

5. Stubborn Weight Issues

Hypothyroidism slows metabolism, making weight management even more challenging for women with PCOS who already struggle with weight due to insulin resistance.

6. Exacerbated Fatigue and Mood Issues

Both conditions can cause fatigue, depression, and anxiety. When combined, these symptoms often become more severe and resistant to standard treatments.

Why Conventional PCOS Treatment Often Falls Short

Standard PCOS treatment typically focuses on birth control pills to regulate cycles, metformin to address insulin resistance, and spironolactone for excess hair growth. While these approaches may help some symptoms, they don't address underlying thyroid dysfunction that could be sabotaging your results.

If you have both PCOS and thyroid dysfunction, treating only your PCOS is like trying to drive a car with the parking brake engaged—you might make some progress, but you'll never achieve optimal results until you address both issues.

Signs You Might Have Thyroid Issues With Your PCOS

Consider thyroid testing if you have PCOS and experience:

•  Persistent fatigue despite adequate sleep
•  Unexplained weight gain or difficulty losing weight despite diet changes
•  Hair loss or thinning (different from male-pattern hair growth of PCOS)
•  Cold intolerance (always feeling cold)
•  Dry skin, brittle nails, or hair texture changes
•  Brain fog and memory issues
•  Depression or anxiety that doesn't improve with standard treatment
•  Constipation
•  Elevated cholesterol levels
•  Family history of thyroid disorders

The Comprehensive Testing Approach

If you suspect thyroid dysfunction might be affecting your PCOS, comprehensive testing should include:

•  Complete Thyroid Panel: TSH, Free T3, Free T4, Reverse T3, Thyroid Peroxidase Antibodies (TPOAb), and Thyroglobulin Antibodies (TgAb)
•  Comprehensive PCOS Evaluation: Total and Free Testosterone, DHEA-S, Androstenedione, Estradiol, Progesterone, Sex Hormone Binding Globulin (SHBG)
•  Metabolic Assessment: Fasting insulin, glucose, HbA1c, and lipid panel
•  Inflammation Markers: hsCRP and homocysteine

Many conventional doctors order only TSH for thyroid assessment and limited hormone testing for PCOS, missing critical information needed for effective treatment.

The Integrated Treatment Approach

When both conditions are present, an integrated approach yields the best results:

1. Optimize Thyroid Function First: Addressing thyroid dysfunction often improves PCOS symptoms and makes other PCOS treatments more effective.
2. Address Shared Root Causes: Target common underlying factors like inflammation, insulin resistance, and nutrient deficiencies.
3. Personalize Treatment Based on PCOS Type: Identify your specific PCOS type (insulin-resistant, inflammatory, adrenal, or post-pill) and tailor treatment accordingly.
4. Consider Medication Interactions: Some PCOS medications can affect thyroid function and vice versa, requiring careful coordination.
5. Monitor Both Conditions Regularly: Regular testing ensures both conditions are improving and treatments remain optimized.

Your Path Forward

If you've been struggling with persistent PCOS symptoms despite following standard treatments, undiagnosed thyroid dysfunction could be the missing piece. At ReNu'd You, we specialize in identifying and addressing these often-overlooked connections.

Our comprehensive approach includes thorough testing of both thyroid and PCOS markers, allowing us to create personalized treatment plans that address both conditions simultaneously. This integrated approach often leads to significant improvements in symptoms that previously seemed resistant to treatment.

Don't let an undiagnosed thyroid condition sabotage your PCOS treatment. Schedule a consultation today to discover if the thyroid-PCOS connection could be affecting your health and well-being.