Thyroid Disorders and Infertility

By Halle Tecco, MBA, MPH

One in eight women will develop a thyroid disorder during her lifetime. Uncontrolled thyroid hormone levels can affect fetal development and can increase the risk of miscarriage, preterm delivery, and other complications during pregnancy. If you have thyroid problems and are hoping to become pregnant, this article will cover what you need to know about fertility and thyroid disorders.

What are thyroid disorders?

Thyroid disorders are conditions that affect the thyroid gland, which is a small butterfly-shaped gland located in the neck. The thyroid gland produces hormones that regulate the body's metabolism, which is the process by which the body converts food into energy. 

There are several types of thyroid disorders, including:

• Hypothyroidism: This is a condition in which the thyroid gland is under-active and does not produce enough thyroid hormone.

• Hyperthyroidism: This is when the thyroid gland is overactive and produces too much thyroid hormone.

• Hashimoto's disease: This is an autoimmune disorder where the immune system creates antibodies that attack thyroid cells. Over time, the inflammation prevents the thyroid from producing enough hormones (hypothyroidism).

• Graves’ disease: This is an autoimmune disorder where your immune system makes antibodies that cause the thyroid to make too much thyroid hormone.

• Goiter: This is an abnormal enlargement of the thyroid gland.

• Thyroid nodules: These are lumps or growths that can occur in the thyroid gland.

• Thyroid cancer: This is a rare type of cancer that affects the thyroid gland.

Signs of thyroid disorders

Symptoms of thyroid disorders can vary widely depending on the type and severity of the condition. Here are some common symptoms: 

• Fatigue: People with hypothyroidism may feel tired and sluggish.

• Weight changes: People with hypothyroidism may gain weight, while people with hyperthyroidism may lose weight.

• Changes in appetite: People with hypothyroidism may have a decreased appetite, while people with hyperthyroidism may have an increased appetite.

• Mood changes: People with thyroid disorders may experience irritability, anxiety, or depression.

• Feeling cold: People with hypothyroidism often feel cold when other people do not.

• Changes in heart rate: People with hyperthyroidism may have a rapid heart rate, while people with hypothyroidism may have a slow heart rate.

• Dry skin: People with hypothyroidism may have dry, rough skin.

• Hair loss: People with hypothyroidism may experience hair loss.

• Changes in the eyes: People with hyperthyroidism can have bulging of the eyes, redness, and/or irritation.

• Changes in menstrual cycle: Women with thyroid disorders may have irregular periods.

If you are experiencing any symptoms, track and share them with your healthcare provider. 

What are normal thyroid levels?

The Natalist at-home fertility test can help you measure your Thyroid-Stimulating Hormone (TSH). Thyroid-stimulating hormone is the pituitary hormone responsible for controlling the production of the hormones T3 and T4 by the thyroid gland. The hormone TSH is considered the most sensitive marker for screening for thyroid diseases and conditions.

The American Thyroid Association recommends serum TSH levels stay 0.4-4.0 mIU/L:

• If TSH levels are below the target range, it may suggest an overactive thyroid

• If TSH levels are above the target range, it may suggest an underactive thyroid.. 

TSH is not the only test for thyroid disease. TSH causes the thyroid gland to make two hormones: triiodothyronine (T3) and thyroxine (T4). T3 and T4 help regulate your body’s metabolism. If your TSH level comes back abnormal, consultation with your healthcare provider and further testing should be considered.

Questions for your provider can include:

• Do I need any additional lab testing or further evaluation of my health? 

• Do I need to go on any new medication(s)? Do you need to make changes to my current medications? 

• Are there any short-term or long-term risks related to these results based on my medical history? 

Ovulation, periods, and thyroid disorders

Irregular ovulation and changes in the menstrual cycle can be a sign of a thyroid disorder, although it is not a definitive sign. The thyroid plays a critical role in regulating the menstrual cycle and fertility, and when the thyroid is out of balance, it can disrupt the normal functioning of the reproductive system. This can lead to irregular ovulation and other fertility issues. 

In women with hypothyroidism, periods may become irregular or stop altogether. In women with hyperthyroidism, periods may become more frequent or more heavy.

However, changes in the menstrual cycle can also be caused by other factors such as pregnancy, menopause, certain medications, and certain medical conditions. If you are experiencing changes in your menstrual cycle, it's important to track and talk to your healthcare provider. 

Hypothyroidism and PCOS

Thyroid disorders and polycystic ovary syndrome (PCOS) are two of the most common endocrine disorders. Both share certain common risk factors and symptoms, like high BMI and increased insulin resistance. And some women with hypothyroidism have polycystic appearing ovaries. Although there is no evidence that hypothyroidism causes PCOS, researchers have found that hypothyroidism is more likely in women with PCOS than without. 

Treatment of thyroid disorders

Treatment for thyroid disorders may involve medication, and the type of medication used to treat thyroid disorders depends on the specific condition being treated. 

Hypothyroidism is a permanent condition requiring lifelong treatment. A common treatment is prescription thyroxine (T4) therapy, also known as levothyroxine. When that doesn’t work, in some cases clinicians will add T3 by prescribing a thyroxine (T4) and triiodothyronine (T3) combination.

Hyperthyroidism can be treated with antithyroid medications (methimazole and propylthiouracil), radioactive iodine ablation of the thyroid gland, or surgical removal of the thyroid.  If you are diagnosed with a thyroid disorder, talk to your healthcare provider about your options.

Thyroid levels and infertility

Fertility specialists will usually test your thyroid levels when doing a fertility workup, as it’s responsible for hormone creation and management. TSH is responsible for controlling thyroid hormone production and can be a reliable indicator of thyroid disease or conditions, as TSH is considered a highly sensitive marker for screening. If you have a thyroid disorder, it’s helpful to get it under control before pregnancy. 

So can you get pregnant with a thyroid condition? Yes, many people with thyroid conditions are able to get pregnant and carry a healthy pregnancy. However, it may be more difficult. 

Abnormal levels of thyroid hormone can:

• Interfere with ovulation and/or disrupt the menstrual cycle, making it harder to get pregnant

• Impact implantation which can lead to early miscarriages

• Increased risk of premature birth

In men, thyroid disorders can affect fertility by affecting testosterone levels and sperm production. An overactive thyroid can cause a decrease in testosterone levels, which can lead to a decrease in sperm production and fertility. An underactive thyroid can also lead to a decrease in testosterone levels and fertility. An at-home sperm test can help determine sperm health. 

It's important to note that while thyroid disorders can impact fertility for both men and women, they can often be treated with medication, which can help restore fertility. Thyroid disorders can be tricky, but they usually do not cause permanent infertility.

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What should I do before getting pregnant if I have a thyroid disorder? 

If you have a thyroid disorder and are hoping to become pregnant, it's important to make sure your thyroid hormone levels are well-controlled before you become pregnant. Uncontrolled thyroid hormone levels can negatively affect fetal development and increase the risk of miscarriage, preterm delivery, and other pregnancy complications.

Here are a few things you can do to prepare for pregnancy if you have a thyroid disorder:

1. Get your thyroid hormone levels checked: Before you become pregnant, it's a good idea to have your thyroid hormone levels checked to make sure they are within the normal range. If your thyroid hormone levels are not within the normal range, your healthcare provider may prescribe or adjust medication to bring them back into the normal range.

2. Take your thyroid medication as prescribed: If you are taking thyroid medication, it's important to take it as prescribed by your healthcare provider. This will help ensure that your thyroid hormone levels remain within the normal range.

3. Talk to your healthcare provider: If you are planning to become pregnant, it's a good idea to discuss your plans with your OBGYN or fertility specialist. They can help you manage your thyroid disorder during pregnancy and can help you make any necessary adjustments to your medication or treatment plan.

4. Be your healthiest self: This goes for all pregnancies! Eating a healthy diet and getting regular exercise can help you maintain good overall health and can also help manage your thyroid disorder.

5. Avoid certain medications: There are some medications that can interfere with thyroid hormone levels or can be harmful to a developing fetus. It's a good idea to discuss any medications you are taking with your healthcare provider to make sure they are safe to take during pregnancy.

6. Make sure you’re taking the right prenatal vitamin. The American Thyroid Association recommends all prenatal vitamins contain 150 mcg of iodine, and the Natalist Prenatal Daily Packs comply. Adequate maternal dietary intake of iodine during pregnancy is essential for maternal thyroxine production and for thyroid function in the fetus. If iodine insufficiency leads to inadequate production of thyroid hormones and hypothyroidism during pregnancy, then irreversible fetal brain damage can result. 

Remember, a diagnosis of a thyroid disorder is not necessarily a diagnosis of infertility. While some people with thyroid disorders have a harder time getting pregnant and keeping a healthy pregnancy, others are able to successfully manage the problem. This is why it’s important to get your thyroid checked and treated if things are abnormal. Wishing you the best on your journey!

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