The Thyroid and Fertility

Around the time of my Hashimoto’s diagnosis at age 27, before I had recovered my health, I had markers and symptoms of premature ovarian insufficiency. I had night sweats, irregular menses, mood swings, as well as an elevated FSH (Follicle Stimulating Hormone: when elevated, this lab can indicate a low ovarian reserve, premature ovarian insufficiency, or menopause).

I was told that there was a good chance that I may never be able to conceive, and many other women with autoimmune thyroid disease are told the same.

Spoiler alert – today I have a happy and healthy seven-year-old son. 🙂 By bringing my thyroid markers into a healthy range and stopping the autoimmune attack on my thyroid gland, I was able to conceive.

The thyroid plays a critical role in our ability to conceive and carry a healthy pregnancy to term, so understanding how to best support the thyroid is an important part of any woman’s fertility journey, and especially for those of us with Hashimoto’s and other thyroid issues.

If you’re thinking about getting pregnant, I cannot emphasize enough the importance of optimizing your thyroid before trying to conceive. Here are some considerations and guidelines for your thyroid health – for the preconception period, during pregnancy, and in the postpartum period.

In this article, we’ll explore:

• The thyroid-fertility connection
• What to consider in the preconception period
• How to support the thyroid during pregnancy
• Postpartum thyroid considerations
• Supporting your thyroid while breastfeeding

What role does the thyroid play in fertility?

The thyroid plays a large role in fertility – in fact, it plays perhaps one of the most important roles! Low levels of thyroid hormone can interfere with ovulation and present fertility challenges. Hashimoto’s, which accounts for 90-97 percent of cases of hypothyroidism, can further affect fertility and pregnancy outcomes because of the presence of thyroid antibodies. ^[1]

Optimizing the thyroid before and during pregnancy can support fertility and healthy pregnancy outcomes, and also prime the body for the postpartum period.

Preconception Period

In the preconception period, the goal is to get the thyroid as healthy as possible before trying to conceive. TSH is often the only test run for the diagnosis and treatment of thyroid conditions, but this test alone does not give a full picture of thyroid health. Insist on a full thyroid panel that includes at a minimum free T4, free T3, reverse T3, thyroid peroxidase antibodies (TPO antibodies), and thyroglobulin antibodies (TG antibodies). If for any reason you are unable to get a full thyroid panel from your doctor, you are also able to self-order a discounted panel I created through Ulta Labs. For more information on essential thyroid tests, see my article.

Please note that some people with Hashimoto’s test negative for thyroid antibodies because their overall immune health is so weak that they do not produce enough antibodies. This is known as seronegative Hashimoto’s.

A thyroid ultrasound can give us more information about the health of our thyroid, and help identify Hashimoto’s in the case that someone doesn’t have antibodies.

According to the Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum, hypothyroid patients who are receiving thyroid hormone replacement medication and who are planning a pregnancy should have their dose adjusted by their provider to optimize serum TSH values to <2.5 μIU/mL. ^[2] Lower preconception TSH values reduce the risk of TSH elevation during the first trimester.

As someone who has been working with hypothyroid patients for over a decade, I have found that most people feel best when their TSH levels are between 0.5 and 2 μIU/mL, so this is the range I typically like to see.

The preconception period is also a good time to implement a high-quality, methylfolate-containing prenatal vitamin, which not only reduces the risk of complications for the baby, but can also be supportive of mom’s health and thyroid function. A few of my favorites are Thorne’s Basic Prenatal, PreNatal Nutrients by Pure Encapsulations, and Prenatal Pro by Designs For Health. (Some of these are available through Fullscript. If you don’t have a Fullscript account, you can sign up with my credentials here.) In addition to a prenatal vitamin, fish oil containing DHA is also important for baby’s brain development, and may also help with mom’s autoimmune and inflammation symptoms. Nordic Naturals is a great, high-quality brand available through Fullscript. (If you don’t have a Fullscript account, you can sign up with my credentials here.)

The Role of Thyroid Autoimmunity in Fertility

As mentioned, Hashimoto’s accounts for 90 to 97 percent of cases of hypothyroidism (the estimate varies depending on the source). Hashimoto’s is a type of thyroid disease that is driven by an autoimmune attack on the thyroid, whereas hypothyroidism is mostly due to insufficient levels of thyroid hormones.

Why is this an important distinction? First, it informs the type of treatment that will be most effective. For those with Hashimoto’s, taking thyroid medication may help temporarily with symptoms, but it does not address the root cause – an autoimmune attack on the thyroid. In order to heal from Hashimoto’s, one will need to stop the autoimmune process.

When it comes to fertility, this distinction is also important because evidence is growing that premature ovarian insufficiency is connected to autoimmune disease. ^[3] Premature ovarian insufficiency (POI) is when a woman shows early signs of menopause, and precedes premature ovarian failure (POF), which is when a woman goes into menopause earlier than expected and will likely struggle with ovulation and fertility. Thyroid disorders are the most common co-occurring conditions with POI, and a deficiency in the hormone DHEA (associated with the adrenals, which are, in my experience, dysfunctional in 90 percent of people with Hashimoto’s) has also been connected. ^[4]

Higher thyroid antibody levels, particularly TPO antibodies, have been associated with an increased risk and severity of POI. ^[5] Several studies suggest a dose-response relationship, where higher titers of thyroid antibodies correlate with:

• Greater likelihood of menstrual irregularities
• Earlier onset of ovarian dysfunction
• More pronounced follicular depletion

In one study, women with high anti-thyroperoxidase antibodies (TPOAb) levels were significantly more likely to have reduced ovarian reserve (e.g. low Anti-Müllerian Hormone [AMH] levels, which means less eggs, and fewer antral follicles, which contain the eggs), even before showing overt signs of POI. ^[6] This suggests that elevated thyroid antibodies may not just be a marker of autoimmunity but could also play a direct or indirect role in ovarian tissue damage. (Read more about the effects of thyroid antibodies in this article.)

Additionally, thyroid antibodies have been found to be directly pathogenic to the reproductive organs. A 2022 study examining thyroid autoimmunity in female infertility and IVF outcomes showed that oocyte fertilization, embryo quality, and pregnancy rates were lower in women with thyroid antibodies than in negative controls, while the rate of early miscarriage was higher. ^[7]

The “follicle hypothesis” suggests that antibodies can actually pass through the blood-follicle barrier, and that the presence of antibodies may create a cytotoxic environment that can damage maturing eggs, thus reducing egg quality and fertilization potential.

See my full article on why thyroid antibodies matter to learn more about the effects of thyroid antibodies on our health.

Reducing Thyroid Antibodies While Trying to Conceive

The good news is that there are a number of ways to reduce thyroid antibodies and support thyroid function. Many of these ways have also been studied to help POI/POF. Here are some strategies that you can implement before and during TTC:

• Diet changes – Removing gluten, dairy, and soy from your diet is one of the first steps I recommend for anyone with Hashimoto’s, as I find that many people are sensitive to these foods.

• Addressing any infections – Infections are common triggers for Hashimoto’s and often are the issue if dietary interventions are not making you feel better. ^[8] These could be oral infections, gut infections, as well as a number of bacterial and viral infections, and they are commonly seen in Hashimoto’s.

• Reducing toxic load – Numerous environmental toxins in our air, water, personal care products, makeup, and cleaning products can overburden our liver and have been found to be triggers for Hashimoto’s and thyroid antibodies. ^[9]

• Reducing stress – Stressors of all kinds can be a trigger for autoimmune issues. Emotional and physical stressors may include big life events like divorce or death, abuse, trauma, sleep deprivation, blood sugar imbalances, too much exercise, or physical trauma. ^[10]

Some key supplements may help reduce thyroid antibodies as well:

• Selenium + Myo-Inositol – Selenium at a dosage of 200 mcg per day has been found to reduce thyroid antibodies in clinical trials. ^[11] In some studies, selenium cut the antibodies significantly within six months. In a study that combined 600 mg of myo-inositol and 83 mcg of selenium to treat Hashimoto’s patients, researchers found that the combination of these two nutrients resulted in decreased TSH, TPO, and TG antibodies, as well as improvements in thyroid hormones and a feeling of personal well-being. ^[12] As a bonus, myo-inositol has been found to be very effective in improving symptoms of polycystic ovarian syndrome (PCOS), and has been found to improve oocyte quality, embryo quality, and pregnancy rates. ^[13] Rootcology’s Selenium + Myo-Inositol contains clinically studied doses of each nutrient.

• DHEA – Thyroid disorders are the most common co-occurring conditions with premature ovarian insufficiency, and a deficiency in the hormone DHEA has also been connected to both. Low levels of the hormone DHEA (dehydroepiandrosterone) may predispose some individuals to developing autoimmune diseases, and supplementing with DHEA may be an effective immune modulation strategy for reducing thyroid antibodies as well. In one study, DHEA was given to women with premature ovarian insufficiency and Hashimoto’s, and those taking DHEA showed a reduction of TPO and TG antibodies. ^[14] Research suggests that 25 mg of DHEA three times per day can increase oocyte quality and quantity. ^[15]
  
  Please note, while this hormone is available without a prescription in the United States and some other countries, I always recommend using it under the supervision of a practitioner due to potential side effects (cystic acne galore, over-conversion to estrogen, and feeding estrogen-sensitive cancers are some potential side effects when used in the wrong person and/or at the wrong dose), and contraindications (like a history of certain cancers). I used DHEA in my 20s and I think it helped me improve my premature ovarian insufficiency. Though I don’t have the labs to prove that, I did have a beautiful son in 2018.

• NAC – N-acetyl-cysteine (NAC) supports healthy levels of glutathione, a key component of the body’s antioxidant defense system. Research has shown that people with Hashimoto’s have lower levels of glutathione. In a study done in 2010, NAC and 15-Deoxy-Prostaglandin J2 (a fatty acid compound with antioxidant and anti-inflammatory properties) exerted a protective effect against autoimmune thyroid destruction in vivo.^[16] Significant associations were seen in the levels of glutathione, as well as TSH and thyroid antibodies. Researchers concluded that the maintenance of a minimal oxidative load was essential to safeguard thyroid cell function. I have seen benefits using 1800 mg per day of NAC. Rootcology’s Pure N-Acetyl Cysteine, which is free of potential reactive ingredients and harmful fillers, is a high-quality option. Studies have shown that NAC can also increase chances of pregnancy because it can improve ovulation quality and increase the number of eggs released.^[17]

• Vitamin D – Vitamin D deficiency is more commonly found in people with Hashimoto’s. Sixty-eight percent of my readers with Hashimoto’s reported also being diagnosed with vitamin D deficiency, and this deficiency has been correlated with the presence of anti-thyroid antibodies. One study found that 92 percent of Hashimoto’s patients were deficient in vitamin D, and another 2013 study found that low vitamin D levels were associated with higher thyroid antibodies and worse disease prognosis.^[18] A more recent study showed that vitamin D supplementation reduced thyroid peroxidase antibody levels in patients with autoimmune thyroid disease.^[19] Vitamin D deficiency also plays a role in fertility, and vitamin D supplementation has been shown to improve pregnancy outcomes in both healthy women and women with PCOS.^[20] Vitamin D supplements can potentially help with fertility, and can help us reduce thyroid antibodies. I’ve personally found that most of my clients who are in remission from Hashimoto’s, keep their levels of vitamin D between 60-80 ng/mL. Pure Encapsulations is a high-quality option.

• Vitamin E – Interestingly, the simple, nonglamorous vitamin E has shown potential benefits for women with POI due to its powerful antioxidant properties. It helps protect ovarian tissue from oxidative stress, which is believed to play a role in follicular decline. Some studies have suggested that vitamin E supplementation may improve ovarian function, support hormone balance (particularly estradiol), and even enhance endometrial thickness, potentially improving fertility outcomes.^[21] Additionally, when combined with other nutrients or treatments like DHEA or CoQ10, vitamin E may further support ovarian health and menstrual regularity in women with POI.

See my full article on strategies to reduce thyroid antibodies for more information, but please keep in mind that not all of these strategies will be appropriate or safe for pregnancy and those wanting to become pregnant.

Emerging Therapies for POI

• CoQ10 (Ubiquinol) – CoQ10 supports mitochondrial function and energy production in oocytes. Studies suggest it may improve egg quality and ovarian response, and potentially raise AMH levels, especially when used alongside assisted reproductive techniques.^[22] The active form, ubiquinol, found in Pure Encapsulations Ubiquinol-QH, is best absorbed. Typical doses range from 100 to 400 mg/day.

• NAD+ – NAD+ (Nicotinamide Adenine Dinucleotide) is a critical coenzyme involved in cellular energy production, mitochondrial function, and DNA repair – processes that are essential for ovarian health and egg quality. In the context of POI, low NAD+ levels may accelerate ovarian aging and contribute to poor follicular development.
  
  Animal studies have shown that increasing NAD+ levels, particularly through supplementation with NAD+ precursors like NMN (nicotinamide mononucleotide) or NR (nicotinamide riboside), can improve ovarian function, increase the number of healthy follicles, enhance oocyte quality, and even restore fertility in models of ovarian aging or insufficiency. ^[23] These benefits are thought to occur by improving mitochondrial efficiency and reducing oxidative damage in ovarian cells. While human research is still emerging, NAD+ support is a promising avenue for women with POI, especially those seeking to preserve or optimize fertility and hormone function. Designs for Health makes a liposomal formulation that contains NMN. (It’s available through Fullscript. If you don’t have a Fullscript account, you can sign up with my credentials here.)

• Melatonin – Melatonin has been shown to protect eggs from oxidative stress and improve mitochondrial function. ^[24] It may support better sleep (which also regulates hormonal balance) and may enhance egg quality in IVF studies. I like Pure Encapsulations Melatonin, which you can take before bed to support sleep.

• Ovarian Platelet-Rich Plasma (PRP) – While not directly involved in reducing thyroid antibodies, ovarian PRP is an emerging regenerative therapy that looks promising for women with POI. It involves injecting a concentrated form of the patient’s own platelets into the ovaries to stimulate tissue repair and rejuvenation. Preliminary studies and case reports suggest that PRP may help reactivate dormant follicles, improve hormone levels such as estradiol and FSH, and even restore menstrual cycles in some women. ^[25]
  
  There have also been documented cases of improved egg quality and spontaneous pregnancies following PRP, both naturally and through IVF. As a minimally invasive and autologous treatment (meaning it is taken from the individual’s own tissues), it carries low risk, and may offer hope to women seeking to conceive with their own eggs, potentially delaying or avoiding the need for donor egg IVF. While larger clinical trials are still needed, PRP is gaining attention as a functional medicine-aligned approach to supporting ovarian function in women with POI. I had this treatment done in 2024, and I do feel it normalized my menstrual cycles. I have to admit I am a bit of a control freak, and I decided to skip anesthesia (because I don’t like to feel “high”), and this was a mistake. It was very painful. Additionally, it took me three days of bed rest to recover. Ovarian stem cell therapy may also be an option, though a bit less available in the US. ^[26]

Thyroid Considerations During Pregnancy

Once you get pregnant, it’s still very important to keep a close eye on your thyroid, especially in the first trimester.

Do NOT wait for a missed period to test for pregnancy, and do NOT wait for your first prenatal visit with your OB/GYN to test your thyroid. In the first 12 weeks of pregnancy, the fetus relies completely on the mother to provide thyroid hormones for its growth and development. Your goal is to confirm your pregnancy as early as possible.

Most OB/GYN practitioners do not schedule the first prenatal visit until eight weeks of pregnancy. Do NOT wait this long to have your thyroid tested. Contact your doctor immediately for thyroid testing as soon as you confirm your pregnancy (or you can self-order a thyroid panel from Ulta Lab Tests).

This is important because most women who become pregnant will need to increase their dose of thyroid medication by about 30 percent, especially in that first trimester. In order to maintain optimal TSH levels throughout pregnancy, some women will require only a 10 to 20 percent increase in dose, while others may require as much as an 80 percent increase. This is why it’s so important to test your thyroid throughout pregnancy.

Insist on regular monitoring of your thyroid levels from your doctor – and don’t just accept “your thyroid is normal” as an answer. Get a copy of your lab results so you can check yourself and see where your numbers are.

According to the American Thyroid Association, the trimester-specific reference ranges for TSH are as follows:

• First trimester, 0.1–2.5 μIU/mL
• Second trimester, 0.2–3.0 μIU/mL
• Third trimester, 0.3–3.0 μIU/mL.

They also recommend thyroid testing approximately every four weeks during the first half of pregnancy because further dose adjustments of thyroid medications are often required. After that, they recommend checking TSH at least once between 26 and 32 weeks of pregnancy.

Preventing Miscarriage with Progesterone

Progesterone plays a crucial role in maintaining a healthy pregnancy, especially in the early weeks, by supporting the uterine lining (endometrium) and reducing uterine contractions. ^[27] Low progesterone levels are a treatable cause of early miscarriage, and may be more common in women with thyroid dysfunction and in women over 35. For women with a history of recurrent pregnancy loss or signs of luteal phase deficiency (such as consistently short luteal phases), bioidentical progesterone supplementation, either orally, vaginally, or via injection, may help support embryo implantation and early pregnancy development. ^[28]

Additional Strategies to Feel Your Best While Pregnant

These are a few other interventions that I have found to be helpful in supporting a happy and healthy pregnancy:

• B6 (or P5P) for Morning Sickness – In researching which supplements are safe and helpful for pregnancy, I came across information about B6 (or the active P5P version) as a preventative for morning sickness. I had already been taking the supplement, so I continued it. Ironically, I did forget to take my supplements the day I was due to give a presentation to hundreds of healthcare professionals, and boy was that a mistake – I had to excuse myself to run to the bathroom with morning sickness mid-sentence! I barely made it to the stall! I was still early in my first trimester and wasn’t showing or announcing the pregnancy yet, but a couple of perceptive doctors caught on that I was pregnant. (One of them actually asked if I was pregnant during the Q&A session after my presentation!)

• Remove Food Sensitivities – Acid reflux was one of my major Hashimoto’s symptoms that bothered me for almost three years, then it went away when I removed reactive foods. I hadn’t had an incident of acid reflux since then, until the end of my first trimester. Before I was pregnant, I had introduced most foods back into my diet, with the exception of gluten and dairy (as well as nuts, which caused me to have chin breakouts), and had no symptoms. But somewhere along the pregnancy, I started to have almost daily acid reflux! I tried some gentle remedies like ginger, magnesium, and drinking more bone broth – to no avail. I asked around quite a bit, and many experts told me that acid reflux just came with the territory! On a hunch, I decided to repeat food sensitivity testing, which revealed that I had a few new food sensitivities! One of them was ginger, a common anti-reflux remedy recommended for pregnant women. I cut out the ginger as well as the other foods that came up positive on the test, and guess what? No more reflux (with the exception of the times I accidentally ate the reactive foods). 🙂

• Healthy Iron Levels – Iron deficiency can cause many “pregnancy” symptoms like brain fog, dizziness, insomnia, fatigue, and restless leg syndrome. Oftentimes, these symptoms are dismissed as normal pregnancy symptoms. When I first became pregnant, I checked my ferritin levels and found they were deficient, so I decided to get iron infusions right away to address the low levels quickly. While I still had the first trimester fatigue (thanks to a big surge of progesterone which helped to prepare the nest for my baby and made me so relaxed, but so sleepy), my mood was really happy and mellow. However, towards the middle of the second trimester, I started becoming emotional and having serious burger cravings! My husband and I dubbed this my “burger deficiency,” and I had to eat two burgers a day to stay calm and happy. (There may have been a time or two where he had to go out in rush hour traffic to get me burgers so I would stop sobbing…)
  
  While the burgers were grass-fed, gluten-free, and delicious, they weren’t enough for the high iron demand the pregnancy caused, and neither were the supplements I was taking. As time went on, I started to feel worse emotionally, eventually having crying spells, anxiety attacks, overwhelm, insomnia, significant fatigue, and even restless leg syndrome that no amount of burgers could resolve. I self-ordered my ferritin and iron labs earlier than recommended by my doctors, and found that I was deficient in iron once more! I began to feel more like myself with each iron IV, and rather quickly, my emotions stabilized, and the anxiety, overwhelm, and insomnia went away. The restless leg was gone after the first IV. Pregnancy and childbirth are both known to deplete iron levels. You may not absorb iron properly from food, no matter how many burgers you eat, and you may not even absorb enough from supplements. Iron IVs are an important option you should know about!

• L-Carnitine – L-carnitine is often depleted in pregnant women and in the postpartum period. I believe that in addition to iron, I was craving so many burgers because of the carnitine! I had already been taking 500 to 1000 mg of carnitine per day (500 mg has been the studied dose in pregnancy research I have seen), but perhaps 2000 mg may have been a more appropriate amount to take due to my history of Hashimoto’s, and because I had to increase thyroid hormones while pregnant.
  
  While I never had my carnitine levels tested, I felt so much better after eating my burgers! After having my son, I stopped eating my burger-enriched diet. I ended up feeling weak and had so much muscle pain and muscle loss that I found my yoga class unbearable. I eventually started taking carnitine and, within days, my muscle pain and weakness resolved, and my muscle strength started building up again. Research has suggested that low iron levels may be the underlying factor in decreased carnitine levels during pregnancy (as iron is a cofactor in the synthesis of carnitine in the body). ^[29] One 2009 study with 26 pregnant women found that those taking 500 mg of L-carnitine during pregnancy, starting at week 13 of gestation through birth, normalized their levels of carnitine. ^[30] (Meanwhile, the placebo group showed continued reductions in their plasma carnitine levels.) If you’re looking for good carnitine supplements, Rootcology’s Carnitine Blend combines 400 mg L-carnitine and 100 mg acetyl-L-carnitine, to support the brain and body.

Postpartum Thyroid Considerations

Taking care of your thyroid in the postpartum period is going to be just as important as preconception and during pregnancy. Postpartum is a common time when women will get diagnosed with Hashimoto’s or thyroid disease.

Postpartum depression is another thing to look out for, and may actually be due to low thyroid hormone. Here are symptoms of postpartum depression to look out for:

• Low mood
• Tearfulness
• Excessive sleeping
• Excessive fatigue
• Irritability
• Worry or anxiety
• Losing or gaining too much weight
• Forgetfulness
• Brain fog
• Feeling apathetic
• Feeling hopeless

In addition to thyroid issues, nutrient deficiencies are another very common cause of postpartum depression, as women tend to be depleted after pregnancy and birth. Another full thyroid panel within a few weeks of giving birth can help catch imbalances early, and here are a few other tests to consider:

• Ferritin – Low ferritin and iron can lead to postpartum depression, and this is a very common nutrient deficiency postpartum.
• Gut testing – The presence of small bacterial overgrowth (SIBO) could lead to postpartum depression.
• Adrenal testing – Low adrenal saliva results may result in symptoms like depression and fatigue.
• Progesterone – Low progesterone levels post-partum can result in postpartum depression.

If getting out of the house to do a blood draw seems impossible, there are options for a phlebotomist to do your blood draw at your home.

Here are some strategies that may be helpful for postpartum thyroid and mood support:

• Selenium – 200 to 400 mcg per day has been found to reduce the incidence of postpartum thyroid issues (and can help reduce thyroid antibodies, as mentioned earlier). ^[31] Pure Encapsulations makes a standalone selenium supplement I like.
• Omega-3s – It is super important to take DHA during pregnancy, and also lowers the risks of postpartum thyroid issues. ^[32] I find that 1 to 4 grams per day is a good range for most people. Opt for a high-quality fish oil like the one from Pure Encapsulations.
• Adaptogens – Adaptogens are herbs that can help support our adrenals and mood, and I found them to be helpful personally in the postpartum period. Please note that for many adaptogens, research is limited on their use in pregnancy and breastfeeding, so please always check with your doctor before using them. That being said, adaptogens that are likely to be safe to take in the postpartum period include ashwagandha, holy basil (tulsi), rhodiola, and schisandra.

In addition to the strategies listed above, I cannot emphasize enough the importance of setting up a support system for yourself and your family for the postpartum period. This may include the support of your partner, family, and friends, meal trains, hiring a doula, getting support at work, and other strategies that allow you to rest as much as possible during this time.

Breastfeeding Considerations

Keeping thyroid hormones at optimal levels is important throughout pregnancy and in the postpartum period, not only for your health and well-being, but also to keep up milk supply. Hypothyroidism can cause low milk supply, while hyperthyroidism can actually cause overproduction of milk. ^[33]

Most thyroid hormone replacement is safe and beneficial in breastfeeding, as long as we are using it in the right amounts. The amount of thyroid hormone in breast milk is not enough to cause harm to your baby, especially if you’ve been stable on your current dose prior to pregnancy.

Hypothyroidism can cause suppressed milk production because it alters the hormones prolactin and oxytocin, both of which are required to produce milk. Suppressed milk production is also likely due to the loss of iodine and thyroid hormones to the milk. Appropriate levothyroxine (T4) replacement can help with this. ^[34]

Most of the research regarding breastfeeding has been done on levothyroxine, and generally, conventional medicine practitioners are fearful of using natural desiccated thyroid hormone (NDT), a combination of both T4 and T3, which can be really helpful for some people who have trouble converting T4 to T3. While a small amount of thyroid hormone is transferred in breast milk, research has found that this does not have a meaningful impact on the baby’s thyroid hormone status.

The American Thyroid Association (ATA) concluded that the amount of thyroxine transferred to a baby during breastfeeding is around one percent of the total daily requirement (based on 2017 ATA Guidelines). ^[35]

The ATA recommends that both subclinical hypothyroidism and overt hypothyroidism be treated with levothyroxine in lactating women planning to breastfeed. ^[36]

Another thing to keep in mind is that hypothyroidism or PCOS during puberty can interfere with the development of glandular tissue, the part of the breast that is responsible for making milk. This can make breastfeeding more challenging, as you may not make as much milk, but it is still possible to have a happy and healthy breastfeeding experience.

Nursing Mother’s Formulary

Other areas of consideration for nursing moms include liver support, adrenal support, gut support, and addressing nutrient deficiencies.

New mamas can gently support their liver by removing any potentially reactive foods, ensuring they’re hydrating properly, and reducing exposure to toxins. Milk thistle tea specifically is safe for nursing moms and supports the liver.

As much as is possible with a newborn, try to sleep and rest as much as you can, and reduce stress where you can. Focus on protein-rich meals to support your blood sugar. Try to squeeze in self-care activities, no matter how small, throughout the day.

Supporting your gut supports thyroid and immune health. We can nurture it by consuming probiotics (either as a supplement or with fermented foods) and incorporating a variety of fruits and veggies in our diet. Other herbs, such as black seed oil and cat’s claw, can be used in the case of a gut infection (I recommend testing by ordering the GI-MAP test).

Additionally, black seed oil is an herb that is safe to use while breastfeeding. It’s actually considered a galactagogue, which means it can help increase milk supply. While breastfeeding-specific data isn’t readily available, it has been shown to be generally well tolerated and to have a low level of adverse effects. I personally used it while breastfeeding to address an H. pylori infection.

There are many potential nutrient deficiencies that can occur in the postpartum period, including vitamin A, vitamin B12, carnitine, choline, fish oil, iron, magnesium, myo-inositol, selenium, thiamine, vitamin C, and vitamin D.

You may continue any prenatal vitamins you were taking during pregnancy, throughout breastfeeding and postpartum, and this may help with these nutrient deficiencies. A few of my favorites are Thorne’s Basic Prenatal, PreNatal Nutrients by Pure Encapsulations, and Prenatal Pro by Designs For Health. (Some of these are available through Fullscript. If you don’t have a Fullscript account, you can sign up with my credentials here.)

You can also do testing for the nutrients listed above and supplement accordingly.

Many nutrients, herbs, supplements, and medications are safe to take while you are breastfeeding. However, there are exceptions, so it is always best to consult with your healthcare provider. Don’t be afraid to get a second opinion and do some extra research yourself if you have concerns.

Check out my nursing mother’s formulary article for more breastfeeding support.

Thyroid and Pregnancy Checklist

Preconception

• Get a full thyroid panel
• Optimize TSH to between 0.5 and 2 μIU/mL
• Reduce thyroid antibodies to less than <100

Pregnancy

• Confirm pregnancy as soon as possible
• Get a full thyroid panel as soon as possible
• Make any medication adjustments to get your TSH in a healthy range
• Continue to test your thyroid every four weeks for the first half of pregnancy
• Test your thyroid at least once between weeks 26 and 32

Postpartum

• Get a full thyroid panel done within a few weeks after giving birth
• Optimize TSH to between 0.5 and 2 μIU/mL

The Takeaway

I understand how disheartening it can be to hear from your doctor that conceiving might be difficult, especially if you’re managing a thyroid condition or facing fertility challenges while dreaming of starting a family.

For many years, I had given up hope that I would ever become a mom.

But through lifestyle changes to address my Hashimoto’s, as well as targeted supplements and interventions to support fertility and ovulation, I was eventually able to conceive and have a healthy baby boy.

The lifestyle changes you’re making for Hashimoto’s are going to help your body become healthier overall, and the healthier you are, the better the chances are for you to conceive and have a healthy pregnancy!

Have you had fertility challenges as someone with a thyroid condition? Which interventions did you find most helpful?

I know this is a sensitive topic for many and if you are still dreaming of starting a family, my heart goes out to you. ❤️

P.S. I love interacting with my readers on social media, and I encourage you to join my Facebook, Instagram, TikTok, and Pinterest community pages to stay on top of thyroid health updates and meet others who are following similar health journeys. For recipes, a FREE Thyroid Diet Quick Start Guide, and notifications about upcoming events, be sure to sign up for my email list!

References

^[1] Ragusa F, Fallahi P, Elia G, et al. Hashimotos’ thyroiditis: Epidemiology, pathogenesis, clinic and therapy. Best Pract Res Clin Endocrinol Metab. 2019;33(6):101367. doi:10.1016/j.beem.2019.101367
^[2] Alexander EK, Pearce EN, Brent GA, et al. 2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum [published correction appears in Thyroid. 2017 Sep;27(9):1212. doi: 10.1089/thy.2016.0457.correx.]. Thyroid. 2017;27(3):315-389. doi:10.1089/thy.2016.0457
^[3] Szeliga A, Calik-Ksepka A, Maciejewska-Jeske M, et al. Autoimmune Diseases in Patients with Premature Ovarian Insufficiency-Our Current State of Knowledge. Int J Mol Sci. 2021;22(5):2594. Published 2021 Mar 5. doi:10.3390/ijms22052594
^[4] Ayesha, Jha V, Goswami D. Premature Ovarian Failure: An Association with Autoimmune Diseases. J Clin Diagn Res. 2016;10(10):QC10-QC12. doi:10.7860/JCDR/2016/22027.8671
^[5] Tańska K, Gietka-Czernel M, Glinicki P, Kozakowski J. Thyroid autoimmunity and its negative impact on female fertility and maternal pregnancy outcomes. Front Endocrinol (Lausanne). 2023;13:1049665. Published 2023 Jan 11. doi:10.3389/fendo.2022.1049665
^[6] Bucci I, Giuliani C, Di Dalmazi G, Formoso G, Napolitano G. Thyroid Autoimmunity in Female Infertility and Assisted Reproductive Technology Outcome. Front Endocrinol (Lausanne). 2022;13:768363. Published 2022 May 26. doi:10.3389/fendo.2022.768363
^[7] Bucci I, Giuliani C, Di Dalmazi G, Formoso G, Napolitano G. Thyroid Autoimmunity in Female Infertility and Assisted Reproductive Technology Outcome. Front Endocrinol (Lausanne). 2022;13:768363. Published 2022 May 26. doi:10.3389/fendo.2022.768363
^[8] Tomer Y, Davies TF. Infection, thyroid disease, and autoimmunity. Endocr Rev. 1993;14(1):107-120. doi:10.1210/edrv-14-1-107
^[9] Brent GA. Environmental exposures and autoimmune thyroid disease. Thyroid. 2010;20(7):755-761. doi:10.1089/thy.2010.1636
^[10] Mizokami T, Wu Li A, El-Kaissi S, Wall JR. Stress and thyroid autoimmunity. Thyroid. 2004;14(12):1047-1055. doi:10.1089/thy.2004.14.1047
^[11] Gärtner R, Gasnier BC, Dietrich JW, Krebs B, Angstwurm MW. Selenium supplementation in patients with autoimmune thyroiditis decreases thyroid peroxidase antibodies concentrations. J Clin Endocrinol Metab. 2002;87(4):1687-1691. doi:10.1210/jcem.87.4.8421
^[12] Nordio M, Basciani S. Myo-inositol plus selenium supplementation restores euthyroid state in Hashimoto’s patients with subclinical hypothyroidism. Eur Rev Med Pharmacol Sci. 2017;21(2 Suppl):51-59.
^[13] Greff D, Juhász AE, Váncsa S, et al. Inositol is an effective and safe treatment in polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials. Reprod Biol Endocrinol. 2023;21(1):10. Published 2023 Jan 26. doi:10.1186/s12958-023-01055-z; Seyedoshohadaei F, Abbasi S, Rezaie M, et al. Myo-inositol effect on pregnancy outcomes in infertile women undergoing in vitro fertilization/intracytoplasmic sperm injection: A double-blind RCT. Int J Reprod Biomed. 2022;20(8):643-650. Published 2022 Sep 6. doi:10.18502/ijrm.v20i8.11753
^[14] Ott J, Pecnik P, Promberger R, et al. Dehydroepiandrosterone in women with premature ovarian failure and Hashimoto’s thyroiditis. Climacteric. 2014;17(1):92-96. doi:10.3109/13697137.2013.800040
^[15] Mamas L, Mamas E. Premature ovarian failure and dehydroepiandrosterone. Fertil Steril. 2009;91(2):644-646. doi:10.1016/j.fertnstert.2007.11.055
^[16] Poncin S, Colin IM, Decallonne B, et al. N-Acetylcysteine and 15 Deoxy-Δ12,14-Prostaglandin J2 Exert a Protective Effect Against Autoimmune Thyroid Destruction in Vivo but Not Against Interleukin-1α/Interferon γ-Induced Inhibitory Effects in Thyrocytes in Vitro. The American Journal of Pathology. 2010;177(1):219-228. doi:10.2353/ajpath.2010.091253.
^[17] Devi N, Boya C, Chhabra M, Bansal D. N-acetyl-cysteine as adjuvant therapy in female infertility: a systematic review and meta-analysis. J Basic Clin Physiol Pharmacol. 2020;32(5):899-910. Published 2020 Nov 19. doi:10.1515/jbcpp-2020-0107
^[18] Chaudhary S, Dutta D, Kumar M, et al. Vitamin D supplementation reduces thyroid peroxidase antibody levels in patients with autoimmune thyroid disease: An open-labeled randomized controlled trial. Indian J Endocrinol Metab. 2016;20(3):391-398. doi:10.4103/2230-8210.179997; Mackawy AM, Al-Ayed BM, Al-Rashidi BM. Vitamin d deficiency and its association with thyroid disease. Int J Health Sci (Qassim). 2013;7(3):267-275. doi:10.12816/0006054
^[19] Wang J, Lv S, Chen G, et al. Meta-analysis of the association between vitamin D and autoimmune thyroid disease. Nutrients. 2015;7(4):2485-2498. Published 2015 Apr 3. doi:10.3390/nu7042485
^[20] Várbíró S, Takács I, Tűű L, et al. Effects of Vitamin D on Fertility, Pregnancy and Polycystic Ovary Syndrome-A Review. Nutrients. 2022;14(8):1649. Published 2022 Apr 15. doi:10.3390/nu14081649
^[21] Md Amin NA, Sheikh Abdul Kadir SH, Arshad AH, Abdul Aziz N, Abdul Nasir NA, Ab Latip N. Are Vitamin E Supplementation Beneficial for Female Gynaecology Health and Diseases?. Molecules. 2022;27(6):1896. Published 2022 Mar 15. doi:10.3390/molecules27061896
^[22] Florou P, Anagnostis P, Theocharis P, Chourdakis M, Goulis DG. Does coenzyme Q10 supplementation improve fertility outcomes in women undergoing assisted reproductive technology procedures? A systematic review and meta-analysis of randomized-controlled trials. J Assist Reprod Genet. 2020;37(10):2377-2387. doi:10.1007/s10815-020-01906-3
^[23] Bertoldo MJ, Listijono DR, Ho WJ, et al. NAD+ Repletion Rescues Female Fertility during Reproductive Aging. Cell Rep. 2020;30(6):1670-1681.e7. doi:10.1016/j.celrep.2020.01.058
^[24] Guo YM, Sun TC, Wang HP, Chen X. Research progress of melatonin (MT) in improving ovarian function: a review of the current status. Aging (Albany NY). 2021;13(13):17930-17947. doi:10.18632/aging.203231
^[25] Éliás M, Kónya M, Kekk Z, et al. Platelet-rich plasma (PRP) treatment of the ovaries significantly improves fertility parameters and reproductive outcomes in diminished ovarian reserve patients: a systematic review and meta-analysis. J Ovarian Res. 2024;17(1):104. Published 2024 May 17. doi:10.1186/s13048-024-01423-2
^[26] Kim HK, Kim TJ. Current Status and Future Prospects of Stem Cell Therapy for Infertile Patients with Premature Ovarian Insufficiency. Biomolecules. 2024;14(2):242. Published 2024 Feb 19. doi:10.3390/biom14020242; Ali I, Padhiar AA, Wang T, et al. Stem Cell-Based Therapeutic Strategies for Premature Ovarian Insufficiency and Infertility: A Focus on Aging. Cells. 2022;11(23):3713. Published 2022 Nov 22. doi:10.3390/cells11233713
^[27] Cable JK, Grider MH. Physiology, Progesterone. In: StatPearls. Treasure Island (FL): StatPearls Publishing; May 1, 2023.
^[28] Barrenetxea G, Prego O, Celis R, et al. Effects of vaginal vs oral progesterone supplementation before embryo transfer on live birth rates and levels: a randomized trial. Reprod Fertil. 2025;6(1):e240094. Published 2025 Mar 20. doi:10.1530/RAF-24-0094
^[29] Berry-Kravis E, Booth G, Sanchez AC, Woodbury-Kolb J. Carnitine levels and the ketogenic diet. Epilepsia. 2001;42(11):1445-1451. doi:10.1046/j.1528-1157.2001.18001.; Qiliang L, Wenqi S, Hong J. Carnitine deficiency in chinese children with epilepsy on valproate monotherapy. Indian Pediatr. 2018 Mar 15;55(3):222-224.
^[30] Keller U, van der Wal C, Seliger G, et al. Carnitine status of pregnant women: effect of carnitine supplementation and correlation between iron status and plasma carnitine concentration. Eur J Clin Nutr. 2009 Sep;63(9):1098-105.
^[31] Negro R, Greco G, Mangieri T, Pezzarossa A, Dazzi D, Hassan H. The influence of selenium supplementation on postpartum thyroid status in pregnant women with thyroid peroxidase autoantibodies. J Clin Endocrinol Metab. 2007;92(4):1263-1268. doi:10.1210/jc.2006-1821
^[32] Hsu MC, Tung CY, Chen HE. Omega-3 polyunsaturated fatty acid supplementation in prevention and treatment of maternal depression: Putative mechanism and recommendation. J Affect Disord. 2018;238:47-61. doi:10.1016/j.jad.2018.05.018
^[33] Thyroid. National Library of Medicine. June 21, 2021. Accessed July 25, 2023. https://www.ncbi.nlm.nih.gov/books/NBK143764/.
^[34] Amino N, Arata N. Thyroid dysfunction following pregnancy and implications for breastfeeding. Best Pract Res Clin Endocrinol Metab. 2020;34(4):101438. doi:10.1016/j.beem.2020.101438; Stuebe AM, Meltzer-Brody S, Pearson B, Pedersen C, Grewen K. Maternal neuroendocrine serum levels in exclusively breastfeeding mothers. Breastfeed Med. 2015;10(4):197-202. doi:10.1089/bfm.2014.0164; Strbák V, Macho L, Uhercik D, Kliment V. The effect of lactation on thyroid activity of women. Endokrinologie. 1978;72(2):183-187.
^[35] Alexander EK, Pearce EN, Brent GA, et al. 2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum [published correction appears in Thyroid. 2017 Sep;27(9):1212]. Thyroid. 2017;27(3):315-389. doi:10.1089/thy.2016.0457
^[36] Moleti M, Di Mauro M, Sturniolo G, Russo M, Vermiglio F. Hyperthyroidism in the pregnant woman: Maternal and fetal aspects [published correction appears in J Clin Transl Endocrinol. 2020 Dec 17;23:100246]. J Clin Transl Endocrinol. 2019;16:100190. Published 2019 Apr 12. doi:10.1016/j.jcte.2019.100190