Hypothyroidism in Women: An Underdiagnosed Epidemic

by: Alejandra Carrasco, M.D. and Christine Maren, D.O.

by: Alejandra Carrasco, M.D. and Christine Maren, D.O.

Physician founders of Hey mami!

If you’re reading this article, chances are you suspect you may have a thyroid problem.

Perhaps you’ve been experiencing symptoms like an inability to lose weight, mood swings, thinning hair, trouble sleeping, anxiety, or extreme fatigue.

And, up until this point you may have chalked this up to stress. Or maybe you asked your doctor for a TSH (thyroid stimulating hormone) test, which came back normal. Yet, your intuition tells you something’s not right.

Well, guess what? Despite your test results there’s a very good chance that something is not right.

The little-known truth is hypothyroidism—a condition in which your body isn’t producing enough thyroid hormone—is extremely common and extremely underdiagnosed in women.


Unfortunately, your thyroid is up against a lot of challenges in our modern world. And measuring a TSH alone is not sufficient.

As you dig a little deeper into the intricate function of the thyroid, you quickly realize that one test cannot possibly account for all the hormonal factors and pathology at play.

In addition, the symptoms of hypothyroidism are vast and can appear random.

The Symptoms of Hypothyroidism

  • Fatigue
  • Depression
  • Brain fog
  • Constipation
  • Dry skin, rashes, mysterious skin conditions
  • Brittle nails
  • Weight-gain and/or an inability to lose weight
  • High cholesterol
  • Thinning or coarse hair
  • Inability to focus
  • Low libido
  • Anxiety
  • Sluggishness in the morning
  • Sensitivity to cold
  • Cold hands and feet
  • Insomnia
  • Muscle pain
  • Fluid retention
  • Thinning eyebrows
  • Hormonal imbalance
  • Mood swings
  • Irregular or painful periods
  • Low heart rate

Comprehensive Thyroid Labs

If we suspect a patient is suffering from postpartum thyroid issues (or any type of thyroid issue), we order 6 different thyroid lab tests:

  1. TSH: though not the end-all-be-all test, it does provide valuable information. TSH is secreted by the pituitary gland (in your brain) to stimulate the thyroid gland to produce T4 and T3.
  2. Free T4: T4 is secreted by the thyroid gland, and the majority of T4 is converted to active T3 for metabolic functions and energy. Low levels of free T4 may mean hypothyroidism.
  3. Free T3 (“the gas”): T3 is the more active form of thyroid hormone that affects your metabolism and energy. Low levels can indicate hypothyroidism or a problem with conversion.
  4. Reverse T3 (“the brakes”): Reverse T3 is also converted from T4 and helps slow down metabolism. Factors that increase conversion of T4 to reverse T3 (i.e. the things that make you slam on the metabolic brakes) include stress, trauma, low-calorie or crash dieting, toxins, infections, inflammation, and certain medications.
  5. Thyroid Peroxidase (TPO) antibodies: This test is to check for autoimmune disease of the thyroid known as Hashimoto’s.
  6. Thyroglobulin (TG) antibodies: This is another marker for autoimmune disease of the thyroid.

Due to the complex nature of thyroid hormones, accompanied by the increased prevalence of hypothyroidism and Hashimoto’s Disease, these six labs are useful tools for achieving an accurate diagnosis and optimizing medication management.

So, please please please insist on all six tests!

The timing of these tests is important, too. If you are already on a synthetic T4 medication like Synthroid or Levothyroxine, we usually recommend labs are drawn first thing in the morning prior to taking your medication. However, if you are taking a medication with T3 (such as Armour or Cytomel), then we like to have these labs checked 4-6 hours after taking medication so that we can better understand T3 levels. Check with your doctor on this one.

If your doctor can’t order these tests for you, then order these yourself or find a doctor who specializes in thyroid conditions to help you. Often a functional medicine physician will be your best ally here as they know which tests to run and how to help you recover. Your job is to advocate for yourself so you can get answers and get better.

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What is Hypothyroidism in the first place?

Hypothyroidism is a clinical state resulting from the underproduction of the thyroid hormone.1

There are a few definitions to be aware of that are well recognized in the medical literature:

  • Overt primary hypothyroidism usually presents with a high TSH and a low free T4. The most common cause of this among women in the United States is an autoimmune disease called Hashimoto’s.
  • Subclinical hypothyroidism on the other hand, presents with a high TSH and a normal free T4.2 Many of the people with subclinical hypothyroidism eventually develop overt hypothyroidism, but are often left untreated until then.
  • Euthyroid Sick Syndrome refers to alterations in low free T3 following severe illness, calorie deprivation, and following major surgeries.3,4. This is not technically an issue with the thyroid gland, but more of a systemic issue with poor conversion. The most common pattern is a low total T3 and free T3 levels with normal T4 and TSH. It has also been referred to as Nonthyroidal Illness Syndrome, Low T3 Syndrome and Wilson’s Temperature Syndrome.
  • Autoimmune Thyroiditis refers to a chronic autoimmune disease – either Hashimoto’s or Grave’s – in which the immune system makes antibodies against the thyroid gland and thyroid hormones. These may include Thyroid Peroxidase (TPO) antibodies, Thyroglobulin (TG) antibodies, and TSH receptor Antibodies (TRAb). This may result in hypothyroidism or hyperthyroidism. But to be clear, this is an immune system problem, that over time alters thyroid function.

Thyroid issues also frequently arise postpartum, which is one reason we feel strongly that women should be screened for this after birth, especially if there is postpartum depression.

And we’re not the only ones. The 2017 Guidelines of the American Thyroid Association state that all patients with depression, including postpartum depression, should be screened for thyroid dysfunction.5 But, again, you will likely need to advocate for all 6 of the tests we outlined above.

What Causes Hypothyroidism?

Beyond pregnancy, pre-existing conditions, radiation, genetics, and congenital disease, other causal factors behind hypothyroidism include:

  1. Autoimmune Thyroid Disease: in Hashimoto’s Disease, over time the immune system destroys thyroid tissue and causes low thyroid function.
  2. Nutrient deficiencies: Production of thyroid hormones relies on adequate nutrients, including iron, iodine, tyrosine, zinc, selenium, vitamin E, C, D and many of the B vitamins. Vitamin A is also important as it improves cellular sensitivity to thyroid hormones.
  3. Tap water containing fluoride and chlorine: Iodine is critical to the production of thyroid hormones. Both fluoride and chlorine can displace iodine from your thyroid, rendering it less effective.6 Fluoride has been shown to disrupt thyroid hormones, even in the standard concentration of less than 0.5 mg/L.7 This is yet another reason we recommend good household water filtration.
  4. Celiac disease: Research has shown that removing gluten from the diet may single-handedly reverse subclinical thyroid conditions in adult patients with newly diagnosed celiac disease!8
  5. Heavy metals: many types of heavy metals are found in our environment, like mercury, arsenic, cadmium and lead. High mercury levels, specifically – which are common in dental materials and large fish like tuna – can lower thyroid hormones.9
  6. Stress: too much stress can cause major thyroid hormone imbalance 10. Stress not only inhibits the production of thyroid hormones, it also tends to increase conversion of T4 to reverse T3, an unusable form of thyroid hormone. For this reason, we often recommend meditation to help you better handle stress, and also adaptogenic herbs like Ashwagandha.
  7. Endocrine-disrupting chemicals: many toxins commonly come from pesticides and plastics and interfere with a variety of thyroid functions.11
  8. Medications: Lithium, iodine and amiodarone may all cause issues with thyroid function.12 Of note: while iodine deficiency can cause hypothyroidism, excessive iodine supplementation may also cause issues.

Why Many Thyroid Issues Go Undiagnosed

In our experience as clinicians, there are many people with suboptimal thyroid function and poor conversion who are undiagnosed and thus left untreated — which leaves a big gap for people who are experiencing the symptoms of hypothyroidism.

Most people are only tested for TSH. That means if there’s another underlying issue, such as autoimmune thyroid disease, it goes unnoticed.

Also, lab ranges do not always represent the ideal. For instance, the normal lab ranges for TSH have been debated for years, but remain mostly unchanged. The upper limit of normal is around 4.5 mIU/L depending on the lab, but many (including published work in the National Journal of Clinical Endocrinology and Metabolism) have suggested a narrower TSH reference range with an upper limit of 2.5 mIU/L is more appropriate.13 The point is: lab reference ranges are not perfect.

Be sure to download our free lab guide to better understand the reference ranges we use with patients in our clinical practices.

We feel strongly about educating you on this matter because thyroid medications can be life changing for some. And when you consider the side effect profile of thyroid medication – when prescribed responsibly and monitored – it is much safer than many other medications (like cholesterol reducing medications and antidepressants, for instance).

The big takeaway…

If you suspect you have a thyroid problem (even if your tests have come back “normal”), write down those thyroid tests we mentioned above and request your doctor run them for you.

And if they won’t, order them on your own or find a functional medicine physician who will.

Again, it is imperative you be your own advocate if you want to figure out what’s going on with your body if the answers aren’t adding up.

No mami needs to be stuck “surviving” on fumes and feeling like crap all the time. Yes, sometimes feeling like crap-warmed-over is inevitable (especially when the kids wake you up three times on the one night you decided to binge watch your favorite show with a half a bottle of wine) but feeling that way all the time? No way. That’s not normal, and it’s no way to live your life.

So, trust your intuition, get those tests run, and find appropriate care if they come back out of range or sub-optimal.

Be sure to download our free lab guide to better understand the reference ranges we use with patients in our clinical practices.

What if your tests all come back as optimal? Then keep digging. Find a functional medicine physician to work with you to look for other issues including mitochondrial dysfunction, undiagnosed Celiac disease, iron deficiency and hormone imbalances.


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Our Bio

We are doctors Alejandra Carrasco M.D. and Christine Maren D.O. We’re board-certified through the American Board of Family Medicine, and certified in functional medicine through the Institute for Functional Medicine. We’re on a mission to support women as they navigate mamihood—from preconception through pregnancy, postpartum, and beyond. As mamis of 3 (each!), we got you.


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