Undiagnosed or poorly managed hypothyroidism is a major reason for infertility, but you can take steps now to improve your chances of getting pregnant.
Hypothyroidism is when your thyroid gland doesn't make enough thyroid hormone. Thyroid hormones regulate your metabolism, which affects how your body uses energy. Thyroid hormones are also involved in the regulation of your menstrual cycle. When thyroid hormone is at optimal levels, the body may skip ovulation, which leads to a missing period. Pretty difficult to get pregnant without ovulating, since the egg is key in conception.
But as someone with hypothyroidism, I am proof that you can still get pregnant. In this article, I will share with you what you need to know about hypothyroidism and pregnancy, including the steps you can take to improve your chances of conceiving.
Causes and Symptoms of Hypothyroidism in Women
The causes of hypothyroidism are different for each woman, but the number one cause of underactive thyroid in women is Hashimoto's thyroiditis1.
Hashimoto's Thyroiditis
Hashimoto's is an autoimmune condition where the body mistakenly attacks the thyroid gland. Autoimmunity means that the immune system is attacking itself. With Hashimoto's, the body produces antibodies that flag the thyroid for destruction. These antibodies are anti-thyroid peroxidase (TPO) and anti-thyroglobulin (TgAb). Once flagged, the immune cells attack and destroy thyroid cells.
The destruction of thyroid cells leads to a decrease in thyroid hormone production, as there are not enough functioning cells to produce the necessary amount of hormones. Over time, enough thyroid tissue is destroyed and the gland can no longer make enough thyroid hormone, resulting in hypothyroidism. It’s generally at this time that medication becomes necessary.
The causes of Hashimoto's thyroiditis are not fully understood, but it is thought to be due to a combination of genetic and environmental factors. Gut health plays a significant role (as you'll learn below), and it is thought that a compromised gut lining may allow bacteria and toxins to enter the bloodstream, which triggers an autoimmune response.
It can take years for Hashimoto's to show up in standard thyroid labs, so it's always critical to test for thyroid antibodies (anti-TPO and TgAb) even if your TSH is in the “normal” range if you have any thyroid symptoms.
Other Causes of Hypothyroid
Other potential causes include surgery, radiation, or certain medications. Lack of iodine in the diet can also cause hypothyroidism, although it's rare. Strong family history or other autoimmune conditions could increase your chances. And sometimes, the cause isn't known.
It's actually quite common to either develop or discover hypothyroidism with pregnancy2 as you need extra thyroid hormone for the growing fetus.
What are Hypothyroid Symptoms?
The thyroid acts like the master of metabolism and affects nearly all the organs in your body, which can make symptoms of hypothyroidism hard to pinpoint.
Symptoms of hypothyroidism in women include:
- Fatigue
- Irregular menstrual cycles
- Miscarriage
- Infertility
- Constipation
- Feeling cold all the time
- Weight gain
- Dry skin
- Hair loss
- Brittle nails
- Brain fog and memory issues
In this article I talk about the 7 common thyroid symptoms that often get missed. If you’re suspecting hypothyroidism, it is worth a read.
Lab Tests for Hypothyroidism
I recommend the following labs for a comprehensive look at your thyroid health:
- TSH
- Total and Free T4
- Total and Free T3
- Reverse T3
- Anti-Thyroid peroxidase (Anti-TPO)
- Anti-thyroglobulin (TgAb)
These labs help to paint a picture of what's happening with your thyroid hormone levels and hopefully catch hypothyroid in its early stages.
In my clinical practice, we test these labs in patients prior to getting pregnant and then retest in early pregnancy, like as soon as someone knows they’re pregnant so we can make necessary adjustments. More on that soon.
What are Your Chances of Getting Pregnant with Hypothyroidism?
Since it's a common reason for infertility, it's natural to worry about your chances of getting pregnant with hypothyroidism. But it's absolutely possible (and I speak from experience) when treated appropriately.
Does Hypothyroidism Affect Fertility?
There are several ways hypothyroidism can impact your chances of getting pregnant—anovulatory cycles, luteal phase defects, hyperprolactinemia, and sex hormone imbalances.
Anovulatory Cycles
An anovulatory cycle is a menstrual cycle without ovulation. Hypothyroid disrupts the menstrual cycle3 because it can interrupt the regular egg release that happens during ovulation. In fact, thyroid hormone is essential for follicle development—making sure the egg is mature enough to be ovulated.
Lack of ovulation impacts fertility because you need to regularly ovulate—or release an egg to be fertilized and implanted—to become pregnant. No ovulation means no egg release. Even if you occasionally ovulate, it can still make it challenging to become pregnant because it's hard to pinpoint when you're fertile.
Here's the good news: if you know you have hypothyroidism and are trying to conceive, you can take steps to increase your chances of getting pregnant. You can significantly improve4 your odds of becoming pregnant with the proper treatment and lifestyle support.
Luteal Phase Defects
The luteal phase is the second half of your menstrual cycle, starting after ovulation and ending the day before your period starts. A luteal phase defect is when the luteal phase is too short—usually due to low progesterone levels. Low thyroid5 levels are linked to luteal phase defects making it difficult to become pregnant.
Hyperprolactinemia
Prolactin is a hormone that's released during breastfeeding. It also plays a role in fertility by helping to mature the egg and keeping the uterine lining healthy. When prolactin levels are too high, it can interfere with ovulation.
Hypothyroid can increase the production of a hormone called thyrotropin releasing hormone6 (TRH). TRH tells the body to release more TSH and prolactin, which can lead to hyperprolactinemia.
Sex Hormone Imbalances
Since thyroid is intimately linked to sex hormones, an imbalance in one can cause an imbalance in the other. For example, sex hormone binding globulin (SHBG), a hormone that carries testosterone and estrogen in the blood, is made in the liver and thyroid helps regulate SHBG. When SHBG is out of balance, levels of bioavailable hormones are thrown off, impacting fertility.
Hypothyroidism and Pregnancy: Here's What to Know
While it's possible to get pregnant with hypothyroidism, there are some risks. I want to emphasize that much of this is based on undiagnosed or untreated hypothyroidism. If you're under the care of your OB/GYN and you have hypothyroidism, they should be monitoring you closely during pregnancy to keep you safe and healthy.
But it's also essential to look at why it is so important to get treated for hypothyroidism before becoming pregnant. The American College of Obstetricians and Gynecologists (ACOG) and the Endocrine Society7 recommend anyone who is pregnant or considering pregnancy be screened for thyroid conditions to make sure that thyroid hormones are within healthy ranges.
Hypothyroidism in Pregnancy Effects on Mother
As you saw earlier, hypothyroidism can increase the chance of miscarriage for pregnant mamas. But the complications of severe untreated hypothyroid for the mother could also include8:
- Pre-eclampsia or high blood pressure
- Anemia
- Postpartum hemorrhage
- Muscle pain and weakness
- Congestive heart failure
- Placental abruption
Hypothyroidism in Pregnancy Effects on Baby
A baby starts to make thyroid hormone on its own about halfway through a pregnancy, but until then, it relies on the mother. If mama has low thyroid hormone, the baby also has a risk of being born with low thyroid hormone levels.
Hypothyroidism in pregnancy effects on baby9 include:
- Premature birth
- Low birth weight
- Cognitive issues due to poor brain development
- Neurological abnormalities
- Breathing problems
- Stillbirth
Once again, this is for severe undiagnosed or untreated hypothyroid.
Labs to Monitor Thyroid During Pregnancy
It is important to have regular lab testing during pregnancy, which includes monitoring your thyroid. A TSH, free T4, and free T3, along with thyroid antibodies should be ordered prior to conception and then continued to be monitored based on those findings. The Endocrine Society recommends running these tests before pregnancy and that TSH should be below 2.5 mIU/L10 during first trimester screening.
Hypothyroidism is associated with an increased risk of miscarriage11 and untreated hypothyroidism can cause issues with embryo development.
If you have a history of Hashimoto’s, meeting with a maternal fetal medicine specialist (MFM) is important as this can create additional complications in your pregnancy. Since TPO antibodies can cross the placenta12, a third trimester ultrasound may be recommended in order to visualize the baby's thyroid.
Thyroid Medication During Pregnancy
Thyroid medication may be necessary to have a healthy pregnancy. If you’re already on thyroid medication, you’ll want to talk to your doctor about monitoring your thyroid and making medication adjustments as needed based on your lab results.
Because T4 is the hormone that crosses the placenta and what baby depends on in early pregnancy, it is important to ensure you have enough T4 available. This is why your doctor may recommend Levothyroxine (synthetic T4) if your TSH and/or free T4 is not optimal.
While I’ve had many patients come to me wanting to start Armour or a natural desiccated thyroid (NDT) hormone, pregnancy is not the time to start a T4/T3 combination medication. The research we have is based on giving T4, which again, is what we know the baby absolutely needs. We also do not want to be adjusting T3 up and down during pregnancy because this can create complications like anxiety, racing heart, heat intolerance, and may be problematic in pregnancy.
If you are already taking an NDT and then find yourself pregnant, your provider will likely choose to keep you on this medication since pregnancy can be a tricky time to switch medications, especially if you have a history of not tolerating other medications. They may add synthetic T4 in addition to your medication should your TSH be elevated or free T4 be lower than 1 ng/dL.
The main take home is that it is important to monitor, leverage medication as needed to maintain the baby's health and your own, and retest with any medication adjustments.
Since postpartum is a common time to see both hypothyroidism and Hashimoto’s arise, this is called postpartum thyroiditis, it is important to continue to monitor thyroid symptoms and labs during this time.
Hypothyroidism Natural Treatments
I'm always a fan of using natural treatments to support the body. While medication is often necessary, natural therapies can help manage symptoms and support healthy thyroid hormone levels.
I want to caution that you don't want to change any part of your treatment plan for hypothyroid without discussing it with your healthcare provider. Never stop taking your medications, especially during pregnancy. Natural options are meant to provide a solid foundation to help support the body. Still, sometimes medications are necessary, and that's okay. You can use many of these therapies alongside your medication, just be sure to check in with your prescribing physician.
Eat a Diet Full of Optimal Nutrients for Thyroid Health
A number of nutrients are critical for optimal thyroid function, so a diet rich in these nutrients is essential for anyone with hypothyroidism.
Some of the most crucial nutrients for thyroid function include:
- Iodine. Iodine13 is one of the most important nutrients for thyroid function. It's used by the thyroid to make thyroid hormone. Some people with hypothyroidism that live in developed nations are deficient in iodine. Iodine deficiency is much more common in developing nations. You can get iodine from eating seafood, seaweed, and iodized salt. During pregnancy and breastfeeding14, iodine needs increase.
At the same time, too much could also be a problem, especially if you are deficient in selenium. It's important not to supplement without the guidance of a healthcare provider and to make sure your iodine intake is balanced with selenium. This is why we include 200 mcg of selenium in our Prenatal Plus alongside iodine to ensure the right balance of these minerals.
- Selenium. Selenium is a micronutrient needed to convert inactive thyroid hormone into an active form. Low levels15 of selenium can mean you make less active thyroid hormone. Since selenium is also an antioxidant, it can help protect the thyroid cells from oxidative damage.
You can find selenium in organ meat, seafood, and brazil nuts (although the amount can vary based on the soil content).
- Zinc. Zinc is critical for many different aspects of thyroid function, including hormone production16 and converting T4 to T3. You can find zinc in oysters, red meat, poultry, and legumes.
- Omega-3 fatty acids. These healthy fats are anti-inflammatory, so they can help cool down inflammation in the body, which is vital when you’re dealing with autoimmunity like Hashimoto's. You can find omega-three fatty acids in fatty fish like wild salmon or sardines, and in plants like chia seeds (but many choose to supplement if they don't eat enough fish).
- Magnesium. Magnesium is a favorite for thyroid health, and studies link low magnesium17 and Hashimoto's risk. People with adequate magnesium18 are less likely to be diagnosed with hypothyroidism.
Plus, it's great for mood, relaxation, and even keeping bowels regular (all important during pregnancy too). Magnesium is found in many foods, including dark chocolate, pumpkin seeds, and leafy greens
For a deep dive into the best foods for your thyroid, check out my article here.
Take Your Prenatal Vitamins
A prenatal vitamin can help fill nutritional gaps to ensure you get the nutrients you and your baby need. It's important to continue taking your prenatal even if you don't think you need it and to start before you become pregnant. You can read more about when to take a prenatal vitamin here.
Nutrient needs go sky high with pregnancy, and sometimes the most nourishing foods are suddenly less than appetizing when you’re pregnant. So it's hard to get all the nutrients you need from food alone.
But not all prenatal supplements are created equal, which is why I created Prenatal Plus. Also, another important hint: take your prenatal away from your thyroid meds, as nutrients like iron and calcium could impair absorption of your medication.
There are many supplements I use to support thyroid health, but not all are safe for pregnancy, so if you have any questions, be sure to ask your healthcare provider.
I created the Thyroid Support supplement with essential thyroid nutrients to provide comprehensive thyroid support.
Stress Management
This is a big one. It's no secret that stress can wreak havoc on our bodies, but managing stress levels is crucial when you have hypothyroidism.
Chronic stress can disrupt the normal functioning of your hypothalamic-pituitary-adrenal (HPA) axis, which can lead to increased levels of stress hormones (e.g. cortisol) and inflammation19 and can further suppress thyroid function20. The HPA axis is the system in which your brain and adrenal glands communicate. In cases of inflammation, autoimmune disease, or prolonged stress, this system can become out of balance. The imbalance is known as dysregulation and can contribute to a whole range of symptoms, including worsening thyroid function. This is also why it can be confusing to understand if your symptoms are due to adrenal and thyroid function.
The events, places, or situations that cause stress in your life can sometimes be beyond your control, but there are steps you can take to help manage them. Exercise, meditation, and relaxation techniques can all help manage stress.
Focus on Gut health
As I mentioned above, there's a close relationship between gut health and thyroid, especially Hashimoto's. Intestinal permeability (often called leaky gut) and inflammation are thought to play a role in the development of autoimmunity. Plus, gut imbalances can also exacerbate the stress response, furthering any HPA axis dysregulation.
It takes time to heal your gut, but you can start supporting it with probiotics, fermented foods, and fiber. If you deal with food sensitivities or digestive issues, you may want to work with a practitioner before getting pregnant to get things under control.
Eat for Blood Sugar Balance
Interestingly, there's a link between impaired blood sugar and hypothyroid21. People with hypothyroidism22 are more likely to develop type 2 diabetes and vice versa. Your thyroid23 is critical for keeping your blood sugar in an optimal range.
Blood sugar balance during pregnancy is especially important for mother and baby, so now is the time to work on stable levels. This means regularly eating throughout the day, including protein and fat at every meal, to help slow down the release of sugar into the bloodstream. It also means avoiding refined carbohydrates and sugary foods as much as possible.
You may need to experiment a bit to find what works for you, but generally, a diet that focuses on whole, unprocessed, fiber-rich foods is a great start.
Final Thoughts on Pregnancy and Hypothyroid
In summary, if you have hypothyroidism and are trying to conceive or are already pregnant, there are some essential things to consider.
First, it's important to work with a healthcare provider who understands thyroid health, especially managing it in pregnancy. You'll likely need to adjust your medication dose as your pregnancy progresses. You may also need additional support in supplements or diet changes.
Secondly, focus on lifestyle factors that can help support thyroid function and manage stress levels. This includes eating a healthy diet, exercising regularly, and managing stress.
Taking these steps to support your thyroid and overall health puts you in the right position to become pregnant and have a healthy, happy pregnancy.
References
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- https://www.reproductivefacts.org/news-and-publications/patient-fact-sheets-and-booklets/documents/fact-sheets-and-info-booklets/hypothyroidism-and-pregnancy-what-should-i-know/#:~:text=Hypothyroidism%20can%20also%20interfere%20with,and%20have%20lowered%20mental%20capacity. ↩︎
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3652173/#:~:text=TPO%20and%20Tg%20antibodies%20are,cross%20the%20placenta%20%5B107%5D. ↩︎
- https://journals.lww.com/greenjournal/Abstract/2020/06000/Thyroid_Disease_in_Pregnancy__ACOG_Practice.47.aspx ↩︎
- https://lpi.oregonstate.edu/mic/minerals/iodine#RDA ↩︎
- https://pubmed.ncbi.nlm.nih.gov/19594417/ ↩︎
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