How Your Thyroid Affects Your Hormones
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How Your Thyroid Affects Your Hormones

By Kylie Serie on Jan 8, 2025Last updated Jan 8, 2025

Wondering how your thyroid affects your hormones? Learn about the critical connection between thyroid health and hormone function, and why it’s essential for fertility and overall well-being. #ThyroidHealth #HormoneBalance #FertilitySupport #ThyroidHormones

By Kylie Serie on Jan 8, 2025Last updated Jan 8, 2025

Your thyroid might be small, but it plays a massive role in your overall health, especially when it comes to your hormones, cycle, and ability to conceive. Many women don’t realize that an underperforming thyroid could be the missing puzzle piece in optimizing their cycle and their fertility.


Let’s break down why your thyroid is so critical to your hormone health:   


What Is the Thyroid, and What Does It Do?

The thyroid is a butterfly-shaped gland located in your neck. It produces hormones—primarily T3 (triiodothyronine) and T4 (thyroxine)—that regulate your metabolism, energy levels, and more. But its influence doesn’t stop there. These hormones play a direct role in:

  • Maintaining healthy reproductive hormone levels.

  • Supporting a regular menstrual cycle.

  • Creating an optimal environment for conception and pregnancy.

When your thyroid isn’t functioning properly—whether it’s underactive (hypothyroidism) or overactive (hyperthyroidism)—it can send ripples through your entire endocrine system, affecting ovulation, cycle regularity, and even your chances of getting pregnant.

 

 

How Thyroid Health Affects Hormones

The thyroid and reproductive hormones are closely connected. Here’s how:

  1. Estrogen and Progesterone: An imbalanced thyroid can disrupt the estrogen-to-progesterone ratio, leading to symptoms like irregular cycles, PMS, or heavy periods.

  2. Ovulation and The Luteal Phase: Thyroid issues can interfere with ovulation and shorten your luteal phase, making it harder for implantation to occur.

  3. Stress Hormones: Thyroid issues often lead to elevated cortisol levels, which can further disrupt reproductive hormones.

 

How Thyroid Issues Impact Your Cycle & Fertility

Optimal thyroid function is essential for a predictable, healthy menstrual cycle & for getting pregnant. Here’s how thyroid issues can affect your cycle & fertility:

  • Irregular Cycles: sub-obtimal thyroid function can lead to long or short cycles

  • Missed Periods: Hypothyroidism can lead to anovulatory cycles (where ovulation doesn’t occur).

  • Heavy or Light Periods: Both extremes are linked to thyroid imbalances, as they affect uterine lining development.

  • Ovulation: Thyroid hormones directly influence the release of eggs during ovulation. Without ovulation, pregnancy isn’t possible.

  • Uterine Lining: A properly functioning thyroid ensures the uterine lining is thick enough for implantation.

  • Pregnancy Maintenance: Hypothyroidism increases the risk of early miscarriage, so optimal thyroid function is crucial for sustaining a pregnancy.

 

Signs Your Thyroid Might Need Attention

If you’re experiencing any of these symptoms, I’d highly recommend digging deeper into your thyroid health. I actually recommend a full thyroid panel as a part of your yearly bloodwork . 

  • Fatigue or low energy.

  • Weight changes (gain or loss) that don’t align with your diet or activity.

  • Hair thinning or loss.

  • Sensitivity to cold or heat.

  • Irregular, heavy, or missed periods.

  • Difficulty conceiving or recurrent miscarriage.

 

Assessing Your Thyroid: 

Like I said above, I would recommend getting a fully thyroid panel (see below) and HTMA done yearly to get the FULL picture of your thyroid health. I also recommend using tighter ranges for thyroid labs as we want to see your thyroid functioning OPTIMALLY. Lastly, I have many clients complete an Iodine Loading Test to assess iodine status. Iodine plays a CRITICAL role in thyroid function and is often a missing piece in healing thyroid issues, optimizing fertility, and having great cycles!

 

 

 

 

 

If you’ve been struggling with hormonal imbalances, irregular cycles, or fertility challenges, addressing your thyroid could be a game-changer. If you’re ready to dig into the root-cause of your symptoms and struggles, I’d love to help you!

 

Apply to work 1:1 HERE!

 

 

-Kylie
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Hi, I’m Kylie—Registered Dietitian and Functional Fertility Practitioner

I help women who’ve been trying to conceive without clear answers uncover what’s really impacting their fertility. Through functional lab testing and a holistic, step-by-step approach, I connect the dots between hormones, thyroid, gut health, and lifestyle—so you know what’s happening and what to do next.

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