Your Thyroid’s Impact on Your Fertility

2023-06-29T11:51:21-06:00December 15th, 2021|

Written by: Dr. Wael Salem, a board certified reproductive endocrinology and infertility specialist at CCRM Fertility of San Francisco

Understanding the Thyroid

What is the thyroid?

The thyroid is a small gland near your throat, shaped like a butterfly, and makes the hormones thyroxine (T4) and triiodothyronine (T3). These hormones plays an important role in regulating energy levels, weight, body temperature, and hair and skin growth. Too much or too little thyroxine can cause health concerns, including your ability to get pregnant. If your doctor is concerned about your thyroid, they may decide to check your thyroid levels. This involves a simple blood test.

The Thyroid and Fertility

Think of the thyroid as the architect of your body’s metabolism. It likes to keep a steady balance of hormones in the body. If thyroid levels are off, it can cause concerns related to your fertility such as:

  • Irregular periods
  • Miscarriages
  • Low sex drive
  • Depression
  • Birth Defects 

Factors related to hypothyroidism

  • Autoimmune disorders
  • Medications
  • Surgery or Radiation therapy 
  • A pituitary disorder 
  • A pregnancy/postpartum state 

Factors related to hyperthyroidism

  • Autoimmune disorders
  • Thyroid nodule making T4
  • A postpartum state 


In hypothyroidism, your thyroid gland isn’t producing enough thyroid hormone (also known as an underactive thyroid). If you have subclinical hypothyroidism, it means while your thyroid is producing enough thyroid hormone, it’s working harder than it should be. Symptoms of hypothyroidism include:


Hyperthyroidism, on the other hand, is when the thyroid produces too much thyroxine (also known as an overactive thyroid). The most common cause of hyperthyroidism is an autoimmune disorder known as Grave’s Disease. If you have hyperthyroidism, you might experience:

  • Nervousness
  • Fast heartbeat
  • Diarrhea
  • Feeling hot

Thyroid lab tests 

Depending on the clinical situation, your doctor may order a thyroid-stimulating hormone (TSH), T4 and/or a thyroid peroxidase (TPO) antibodies. 

Evaluating the Thyroid study

If your TSH is high and your T4 is low, it would generally indicate that you are experiencing a state of hypothyroidism. Conversely, if the TSH is decreased and the T4 is low, it could indicate hyperthyroidism. A state in which the T4 is technically within the normal range but the T4 is either too low or too high would indicate a “subclinical” state which can still impact your fertility. 

TPO antibodies

If you have TPO antibodies in your blood, it means you could have an autoimmune disorder that affects your thyroid, such as Hashimoto’s disease. If your TSH is elevated or if you have subclinical hypothyroidism, your doctor may perform a TPO antibody test.

Treating thyroid conditions

Levothyroxine (Synthroid) is a medication similar to thyroxine and helps stabilize thyroxine levels. It can take about eight weeks after starting to have its intended effect to get your body back in natural balance. For this reason, it’s important for your doctor to monitor your levels when you’re just starting out or adjusting the dose.  

Thyroid supplements such as crushed bovine thyroid aren’t recommended since these supplements aren’t regulated by the FDA and can vary in the dosage of thyroid hormone you take. 

It’s important to take your thyroid medication correctly. 

  • Take it in the morning at least one hour before you eat or drink anything besides water. 
  • Swallow it with a full glass of water and don’t crush the tablet. 
  • Vitamin C can affect absorption, so avoid drinking orange juice for several hours after taking your medication. 

If you’ve been taking thyroid medication for a few months and haven’t become pregnant, consider having your thyroid levels rechecked. You might need to adjust your medication until you’re in an optimal range. 

However, if your thyroid levels have been stable for several months, you have regular periods and you’re under age 35, you should consider seeing a fertility specialist after one year of infertility. If you’re over 35, you shouldn’t wait more than six months before consulting about your fertility.  

If you’re concerned about your thyroid’s impact on your ability to get pregnant, make an appointment with a CCRM Fertility specialist to get started on a personalized treatment plan to grow your family. 

About CCRM

CCRM is one of the industry's leading pioneers in fertility science, research and advancement, offering access to a national network of award-winning physicians, a full suite of fertility services, innovative technology and cutting-edge labs.

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