In this article:
- How the thyroid affects the female reproductive system
- Regulating your menstrual cycle when you have hypothyroidism
- Infertility in males with thyroid disease
- Where to start if you are struggling to conceive
The thyroid is a small, albeit mighty, endocrine gland located at the nape of your neck. This organ produces and secretes thyroid hormones, which direct cellular growth and metabolism. Thyroid hormones reach every organ system in your body, including your reproductive system.
When thyroid hormone levels are too high (hyperthyroidism) or too low (hypothyroidism), it can affect your fertility. Indeed, having a healthy thyroid is a prerequisite for being fertile. While thyroid disease can lead to infertility, people with a thyroid condition may find their fertility outcomes improve remarkably after treating their underlying thyroid disease with thyroid hormone replacement medication.
How the Thyroid Affects the Female Reproductive System
The hypothalamus-pituitary axis (HPA) controls the thyroid gland. The hypothalamus is located in the brain and produces specific hormones that send information to the pituitary, another gland located in the brain. Once the pituitary receives communication from the hypothalamus, it sends hormones to various organs in the body.
The HPA is responsible for directing the thyroid. Based on the information received from the hypothalamus, the pituitary releases thyroid-stimulating hormone (TSH) to signal the thyroid to make more or less thyroid hormone.
Aside from controlling the thyroid, the pituitary also releases gonadotropins, which are hormones related to fertility. Examples of gonadotropins include luteinizing hormone (LH) and follicle-stimulating hormone (FSH). When anything disrupts the careful balance of hormones, it can affect the hormones that control the menstrual cycle. Even slight changes in TSH (as found in subclinical hypothyroidism) can affect the reproductive system.
Thyroid dysfunction can affect female fertility through:
- Anovulation, where you do not release an egg each menstrual cycle
- Luteal phase defects, where your ovaries do not produce enough progesterone or the uterine lining does not respond to progesterone appropriately
- High prolactin levels, which can prevent you from conceiving
- Sex hormone imbalances
Women need to have a complete menstrual cycle to conceive. However, women with hypothyroidism often have irregular or missed periods. Women cannot ovulate without a regular menstrual cycle and build up their uterine walls to support pregnancy after conception.
Regulating Your Menstrual Cycle When You Have Hypothyroidism
While there is no cure for hypothyroidism, you can successfully manage this condition by taking thyroid hormone medication. Once you are on the correct dose of medicine, you will likely see your menstrual cycle normalize. Restoring balance to your thyroid hormones can also inhibit prolactin production and prevent luteal phase defects.
People with subclinical hypothyroidism are not always treated with medication unless they are symptomatic. However, having irregular periods or struggling to conceive may be a sign that subclinical hypothyroidism affects your body. In one study of nearly 400 women with either subclinical or overt hypothyroidism, 76% could conceive within six weeks to one year after starting thyroid medication.
Infertility in Males with Thyroid Disease
Although women are more likely to be diagnosed with a thyroid condition, men can also be affected by thyroid disease and infertility. Like women, the HPA controls thyroid hormone and sex hormone production in males.
When T4 and T3 levels are off, it can affect early development and overall functioning in the testes. Too much thyroid hormone (hyperthyroidism) can affect sperm count, motility, morphology, and volume. Conversely, too little thyroid hormone can change sperm morphology, making it difficult for sperm to successfully reach and unite with an egg.
Correcting thyroid hormone levels with thyroid hormone medication can improve sperm quantity and quality, increasing your chance of fertilizing an egg.
Where to start if you are struggling to conceive?
Most doctors do not proactively check your thyroid function if you are under age 35 unless you have:
- Symptoms of a thyroid condition
- A history of autoimmune disease
- A positive family history of thyroid disease
Therefore, if you suspect you may have problems with your thyroid, connect with your doctor as early as possible to increase your chances of conceiving. Suppose your TSH levels are even slightly off on your thyroid blood test. In that case, your doctor may go ahead and treat you with thyroid hormone medication to regulate your period and restore hormonal balance in your body.
Aside from a thyroid disorder, there are so many factors that can affect your fertility. Therefore, it is helpful to meet with your doctor before you try to become pregnant. Your doctor can help identify any risk factors that may affect your ability to get pregnant and guide you on taking the right prenatal vitamins.
Additionally, specific lifestyle habits can increase your chances of conceiving and carrying a healthy baby to term. These habits include:
- Smoking cessation
- Avoiding alcohol consumption
- Getting regular exercise to keep you at a healthy weight
- Reducing your stress levels
- Eating a balanced diet of wholesome foods.
Infertility is hard to navigate, both physically and emotionally. If you are struggling to conceive, meet with a trusted thyroid doctor to optimize your thyroid health.