Thyroid Health in Pregnancy and Postpartum

Thyroid health is a central player in maintaining a healthy pregnancy and thriving postpartum. Unfortunately, thyroid health often gets glossed over and doesn’t receive the thorough investigations that are sometimes warranted.


Let’s dive into some essential information you should know about your thyroid:

  • What the thyroid gland is and why it’s important 

  • Symptoms of an under-functioning and over-functioning thyroid 

  • Thyroid changes during pregnancy

  • Why and when to check thyroid levels postpartum

  • Lab work beyond TSH (thyroid stimulating hormone)

Thyroid Health 101 

The thyroid gland is a small, butterfly-shaped organ in your neck that produces thyroid hormones (T3 and T4). Thyroid hormones have many crucial roles in the body, including regulating metabolism, body temperature, digestion, and heart rate, just to name a few. 


The thyroid is like the thermostat of the body. When it's underperforming (also known as hypothyroidism), everything slows down and leads to bloating, constipation, dry skin, brittle hair and nails, depressed mood, weight gain, and low energy.


When the thermostat is working on overdrive (aka too much thyroid hormone in the body/hyperthyroidism), it can lead to anxiety, unintentional weight loss, sweating, fast and irregular heartbeat, fatigue, muscle weakness, increased appetite, increased bowel movements, and irregular menses.

Thyroid Demands Go Up During Pregnancy

An optimally functioning thyroid is a critical component of a healthy pregnancy. Thyroid hormone demands go up during pregnancy, which is why most women are routinely screened for TSH (thyroid stimulating hormone), to make sure it’s in the optimal range to support pregnancy. 


One of the primary reasons it’s routinely screened is that it’s critical to babies’ development and preventing the risk of preterm birth.


If you are already on medication for hypothyroidism (an underactive thyroid) during pregnancy, it’s standard for your primary care provider to increase your dose, to meet the increased thyroid demands during pregnancy. 


Naturopathic Doctors like to see TSH levels between the reference range of 0.32-2.5 mU/L, although it’s essential to note reference ranges can differ based on location. Levels above 2.5 mU/L may be flagged as normal… therefore it might be necessary to advocate for yourself and work with a practitioner willing to dive deeper into the lab work to ensure no abnormalities are missed.

Why TSH isn’t the Whole Story

TSH is the standard thyroid test most Doctors do, but it’s not the whole story surrounding thyroid health. Sometimes, more comprehensive lab work is needed.


When TSH is in a “grey zone”, meaning borderline levels or slightly elevated, not all healthcare providers will run additional thyroid testing. Seeking an endocrinologist or Naturopathic Doctor to order further thyroid testing can be helpful; consulting these specialists is especially important if TSH levels are in the "grey zone." Although there are plenty of natural and holistic ways to support thyroid health, sometimes pharmaceuticals are needed to achieve optimal levels. Treating thyroid abnormalities promptly is essential, as they can have a significant impact on how you feel and your babies health. 

Thyroid Lab-work 

TSH (thyroid stimulating hormone) 

TSH is like a messenger that tells your thyroid gland to produce thyroid hormones. If TSH is high, it usually means your thyroid might be underactive; if it’s low, it might be overactive.


TPO Ab (thyroid peroxidase antibodies) 

TPO antibodies are like little markers indicating if your body's immune system is mistakenly attacking your thyroid. This happens in conditions like Hashimoto's thyroiditis. High levels mean there might be an autoimmune issue affecting your thyroid.


T4 (thyroxine) 

T4 is one of the main thyroid hormones. Think of it as a storage hormone waiting to be converted into an active form (T3). High or low levels can indicate if your thyroid is making the right amount.


T3 (Triiodothyronine)

T3 is the active form of thyroid hormone that affects your body's metabolism. It's like the 'worker' hormone that influences how your cells use energy. Checking T3 levels helps understand if your thyroid is doing its job correctly.


Reverse T3 

Reverse T3 is like a brake on the active thyroid hormone (T3). Sometimes, stress or illness can make the body produce more reverse T3, slowing down the thyroid's effect. It helps to see if there's an issue with the conversion of hormones.

The Wild Ride of Thyroid Changes Postpartum

Thyroid hormones can go up, down, and up again, leaving you feeling like you are on an energy rollercoaster. Although there is so much happening postpartum, ensuring thyroid levels aren’t contributing to the wild ride that is postpartum is vital. 


For symptomatic patients, at 6-8 weeks postpartum, it’s ideal to check TSH, T4 and TPO Ab. In addition, if anything is out of range or you have any suspicious symptoms that may indicate a thyroid issue, it’s essential to recheck thyroid levels again between 2-6 months postpartum. 


Some symptoms postpartum that would warrant a thyroid investigation include:

  • Low milk supply 

  • Fatigue 

  • Racing heart 

  • Insomnia 

  • Trouble concentrating or focusing 

  • Depression

  • Type 1 diabetes

  • Autoimmune disease

  • Previous diagnosis of a thyroid condition

5 Key Take-Aways

  1. Optimal thyroid hormone levels are an important part of a healthy pregnancy and postpartum experience. 

  2. TSH is the only lab test run for low milk supply, as thyroid hormones directly impact lactation.

  3. TSH (thyroid stimulating hormone) is routinely run in most pregnant women, but it isn’t the whole story. Further thyroid lab work is sometimes needed.

  4. There are many ways to support the thyroid naturally through nutrients like iodine, selenium, zinc and myo-inositol. It’s essential to work with a practitioner who understands the ideal dose, type, and duration of thyroid-supporting supplements. 

  5. Medication is sometimes needed to bring thyroid levels back to the ideal range.

You Deserve Compassionate and Evidence-Based Support

If you're experiencing any symptoms or simply feel you could be at your best, reach out to a compassionate healthcare provider who takes a holistic approach to your well-being. Mama, you deserve to feel like the best version of yourself because when you feel well, everything is possible.