Why Thyroid Health Matters in Pregnancy and Postpartum

Your thyroid is a butterfly shaped gland located at the front of your neck. It produces several hormones that are crucial to maintaining your metabolism as well as helping to regulate other hormonal systems in the body.

During pregnancy, your thyroid gland ramps up production of hormones by more than 50% to support your own body and your baby’s development. For the first half of pregnancy, your baby is entirely reliant on your thyroid hormones. Around weeks 16-20 the fetal thyroid gland becomes mature enough to produce its own hormones. Interestingly, changes in thyroid hormones during early pregnancy can also contribute to morning sickness, which tends to end in the late First Trimester or early Second Trimester. 

Thyroid concerns in pregnancy aren’t often discussed, but they are common and can extend into postpartum. Studies have shown that up to 23% of all new mothers experience thyroid dysfunction postpartum, a significant increase from 3-4% in the general population. 

Below, we walk through common thyroid concerns to be aware of during pregnancy and postpartum, how to support your thyroid during and after pregnancy, and how to advocate for your thyroid health-including through thyroid testing. 

Underactive Thyroid During Pregnancy

Due to the increased demands on the thyroid during pregnancy, the most common thyroid complication that results is hypothyroidism, or an underactive thyroid. This has implications for both mama and baby.

Hypothyroidism during pregnancy has been associated with miscarriage, low birth weight, anemia, preeclampsia, gestational hypertension, postpartum hemorrhage, congenital circulation defects, fetal distress, preterm delivery, and an increased risk of cesarean section.

Hypothyroidism during pregnancy can also affect baby’s brain development, as this process is highly dependent on mama’s thyroid hormone levels. Implications from disrupted brain development can result in a variety of neurodevelopmental problems such as cognitive delays, delayed verbal development, impaired motor skills, autism, and attention-deficit hyperactivity disorder (ADHD.)

Postpartum Thyroiditis

Thyroid dysfunction in postpartum is often referred to as postpartum thyroiditis. Even if your thyroid function was normal throughout pregnancy, problems can still arise postpartum as all of your hormones go through a significant adjustment. That said, the risk of postpartum thyroiditis is higher if problems did exist in pregnancy. In fact, the risk of developing postpartum thyroiditis increases by 40 to 60 percent if dysfunction was identified in the first half of pregnancy. 

Postpartum thyroiditis can be hard to identify without testing as symptoms mimic many common complaints during this time - extreme fatigue, depression, hair loss, difficulty losing weight, and trouble producing sufficient breast milk. But it's important to know that dysfunction is quite common (as high as 23% of all new mothers experience thyroid dysfunction postpartum, a significant increase from 3-4% in the general population). 

How to Support Your Thyroid During and After Pregnancy

Supporting your thyroid during pregnancy and postpartum means providing it with the nutrients it needs for proper function. Two key nutrients include Iodine and Selenium. Our Prenatal Multi contains 290mcg of Iodine as Potassium Iodide. We chose this form as it is well absorbed with a consistent amount of Iodine. While some prenatal vitamins source Iodine from kelp, studies have found wide variations in the content of Iodine found in kelp.  We chose this amount of Iodine as many pregnant women actually lack Iodine in their diets due to avoiding processed foods and favoring Himilayan salt instead of iodized table salt.  Many other foods that are high in Iodine such as seaweed and fish are not tolerated by many pregnant women. But even if you are a big seafood or dairy eater, this dose is still safe. We found that it was more protective than other prenatal vitamins while also allowing quite a bit of space to obtain Iodine through diet before reaching the daily upper limit (UL) of 1,100 mcg/day. Our Prenatal Multi also includes 200mcg of Selenium in the most well absorbed form, L-selenomethionine. 

It’s also worth noting that Selenium can have a protective effect against excess Iodine. When Iodine from foods and supplements is processed by the thyroid gland, hydrogen peroxide, a free radical, is released. If too much Iodine is consumed, the excess hydrogen peroxide that is released can be detrimental. However, if the body has adequate levels of Selenium, the Selenium can neutralize the hydrogen peroxide. Therefore, pairing supportive doses of these two nutrients as we do in our Prenatal Multi can help support thyroid health.

Finally, it’s worth noting that proper nutrition supports thyroid function, but does not necessarily prevent dysfunction, so testing and monitoring for symptoms is always recommended.

How to Check Thyroid Function

Thyroid Testing

The only sure way to know if your thyroid is functioning appropriately is to get tested with a full thyroid hormone panel. A full panel gives you a comprehensive picture of how your thyroid is functioning, and also shows whether or not you have thyroid antibodies: thyroid peroxidase antibody (TPO) and thyroglobulin antibody (TGAb). The presence of thyroid antibodies are strongly linked to the development of thyroid issues postpartum.

As thyroid hormones can shift dramatically over the course of conception, pregnancy, and postpartum, it is recommended to test before, during, and after pregnancy. Unfortunately, this is not typical in many medical practices. We encourage you to ask your doctor or midwife to check your hormone levels. If testing through your provider is not accessible, there are at-home tests available for you to test yourself.

Look for Symptoms 

While many women with hypothyroidism have no obvious symptoms, or at least none that can be easily distinguished from other common pregnancy and postpartum symptoms, it’s helpful to know what they are so that you can be aware and bring up any concerns with your provider. 

Signs of an underactive thyroid include feeling extremely cold or hot, becoming easily fatigued, a lack of change in appetite, anxiety, irritability, depression, tremor, rapid heart rate or palpitations, dry skin, and difficulty concentrating. 

If you already have known thyroid dysfunction

If you already have a known thyroid condition, it's very important to work with your provider to actively monitor your existing protocol, as it will likely need to be adjusted throughout pregnancy and postpartum. In addition, as too much iodine can be as detrimental as too little, we recommend monitoring your intake of other high iodine foods (seaweed, seafood, spirulina, dairy, etc) and discussing supplementation of both Iodine and Selenium with your provider. 

Be your own advocate

This information is intended to empower you to advocate for your own health and your baby’s health throughout preconception, pregnancy and postpartum. A properly-functioning thyroid is critical for your own health and fetal development during pregnancy, and for sufficient energy, mental health, supporting a healthy weight, and remaining fertile for any future pregnancies. Don’t hesitate to get your thyroid tested before, during, and after pregnancy and support it throughout this entire time period with a high quality prenatal vitamin.