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Thyroid and Fertility: What's the Connection?

Medically reviewed on February 17, 2022 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

The thyroid gland is a small, butterfly-shaped organ located in the neck. It produces hormones that regulate a variety of vital functions in the body, ranging from metabolism to ovulation [1].

Unfortunately, the thyroid doesn’t always produce the optimal amount of hormones needed to regulate the body. If the thyroid is underactive or overactive, a thyroid condition may develop and you may experience a slew of unpleasant symptoms.

But is infertility one of them? If you think a thyroid problem may be contributing to infertility, it helps to know how they can relate to each other. Getting a fertility test and seeking the advice of a specialist can give insight into thyroid and fertility problems. Below, we’ll explore the connection between the thyroid and fertility in detail.


Thyroid disorders: hyperthyroidism and hypothyroidism

According to the American Thyroid Association, over 12% of Americans will develop a thyroid disorder at some point in their life [2]. The two main types of thyroid disorders are hyperthyroidism and hypothyroidism.

Let’s look at how these two thyroid disorders differ.


Hyperthyroidism is a thyroid disorder characterized by an overactive thyroid, one that releases too much thyroid hormone. Roughly 1 in 100 people suffer from this condition [3]. It’s commonly caused by an autoimmune condition known as Graves’ disease [4].

Some possible signs of hyperthyroidism include [5]:

  • Light menstrual cycles
  • Unexplained weight loss
  • Frequent sweating
  • Heat intolerance
  • Unexplained anxiety or nervousness
  • Increased appetite
  • Sleeping problems


In contrast, hypothyroidism is characterized by an underactive, sluggish thyroid. This condition affects nearly 1 in 20 Americans [3], and is often caused by an autoimmune disorder called Hashimoto’s disease [6].

Symptoms of hypothyroidism can include [7]:

  • Heavy menstrual cycles
  • Unexplained weight gain
  • Cold intolerance
  • Fatigue
  • Forgetfulness
  • Constipation
  • Dry, pale skin
  • Thinning hair

How do thyroid disorders impact fertility?

Thyroid disorders can impact fertility in different ways depending on one’s sex.

For those assigned female at birth, having optimal thyroid levels is crucial when it comes to successfully getting pregnant. This is because individuals with thyroid imbalances are more likely to experience [2]:

  • Menstrual cycle disruptions
  • Anovulation (the absence of ovulation)
  • Problems with fertilization or implantation
  • An increased risk of miscarriage or premature birth
  • An increased risk of having a baby with developmental problems

It may be a good idea to get your thyroid levels checked before trying to conceive if you have symptoms of a thyroid disorder, but talk with a healthcare provider to learn what they recommend.

If your thyroid levels are out of balance, you may be able to work with a healthcare provider to restore them before pregnancy, giving you a better chance of having a healthy, full-term pregnancy.

While thyroid disorders are less common in those assigned male at birth, they can still occur and cause fertility issues. Most notably, an underactive thyroid can [8]:

  • Harm a person’s sperm count and quality
  • Reduce a person’s testicular and erectile function

These issues may make it more difficult to get pregnant. Fortunately, certain medications can regulate thyroid levels and help prevent these fertility issues.

Subclinical hypothyroidism and fertility

Some experts believe that the “normal” thresholds for thyroid hormone levels are too wide, especially for people who are trying to get pregnant. This is because it appears that subclinical hypothyroidism may impact fertility, as well [9].

Subclinical hypothyroidism is a mild form of hypothyroidism in which a person’s levels of thyroid-stimulating hormone (TSH) are in the upper part of the normal range.

Thyroid dysfunction and pregnancy

If a person with a thyroid disorder successfully becomes pregnant, they can take steps to ensure the pregnancy goes smoothly and the baby is born healthy.

For instance, a healthcare provider can monitor their thyroid levels throughout the course of the pregnancy and continuously adjust their thyroid medication to ensure levels remain optimal.

Treatments for thyroid disorders

If you have a thyroid disorder and want to get pregnant, you should enlist the support of a healthcare provider early in the process. They may recommend that trying to optimize your health before getting pregnant by:

  • Taking thyroid-regulating medication [10]
  • Eating a balanced diet
  • Being physically active
  • Reducing your stress levels

After pursuing a healthcare provider’s treatment plan, you can re-test your thyroid levels and see if they’ve improved. Associated fertility issues often subside once thyroid levels are back on track.

You don’t need to let go of your dreams of having a family just because you’re experiencing a thyroid disorder. All you need to do is take care of your thyroid health before, during, and after pregnancy with the help of a healthcare provider.

Everlywell: take control of your fertility today

While irregular thyroid function may be causing infertility, there are treatment options. If you still have trouble getting pregnant after treating a thyroid disorder, your infertility may be due to another condition. You can check your TSH levels, as well as many other important hormone levels, with an at-home test kit from Everlywell. Our Women’s Fertility Test measures the following key fertility hormones:

  • Estradiol
  • Luteinizing hormone
  • Follicle-stimulating hormone
  • Thyroid-stimulating hormone
  • Total testosterone

If any of these hormones are out of balance, a healthcare provider can better determine how to optimize fertility and increase the chances of getting pregnant.

What is secondary infertility?

Fertility awareness methods

Can irregular periods cause infertility?

When to see a fertility specialist

What affects fertility?


1. How does the thyroid gland work? InformedHealth.org [Internet]. URL. Accessed February 17, 2022.

2. General Information/Press Room. American Thyroid Association. URL. Accessed February 17, 2022.

3. Thinking About Your Thyroid. National Institutes of Health. URL. Accessed February 17, 2022.

4. Graves’ Disease. National Institutes of Health. URL. Accessed February 17, 2022.

5. Hyperthyroidism. MedlinePlus. URL. Accessed February 17, 2022.

6. Hashimoto's Disease. National Institutes of Health. URL. Accessed February 17, 2022.

7. Hypothyroidism. MedlinePlus. URL. Accessed February 17, 2022.

8. Krajewska-Kulak E, Sengupta P. Thyroid function in male infertility. Front Endocrinol (Lausanne). 2013 Nov 13;4:174. PMID: 24312078; PMCID: PMC3826086.

9. Maraka S, Singh Ospina NM, Mastorakos G, O'Keeffe DT. Subclinical Hypothyroidism in Women Planning Conception and During Pregnancy: Who Should Be Treated and How? J Endocr Soc. 2018 May 3;2(6):533-546. PMID: 29850652; PMCID: PMC5961023.

10. Thyroid Disease & Pregnancy. National Institutes of Health. URL. Accessed February 17, 2022.

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