Postpartum thyroiditis is an inflamed thyroid gland that can occur in people after they give birth. It may last for 12–18 months after delivery.

Postpartum thyroiditis can cause the thyroid gland to make an excess of thyroid hormones and can later lead to an underactive thyroid. In many cases, the condition resolves within 12–18 months of childbirth.

This article looks at the symptoms, causes, and diagnosis of postpartum thyroiditis, as well as treatment and outlook.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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Postpartum thyroiditis is inflammation of the thyroid gland after giving birth.

The thyroid gland is a small gland in the front of the neck that produces thyroid hormones. Thyroid hormones help the body to use energy and support the functioning of organs.

If the thyroid gland produces too many or too few thyroid hormones, it can cause systems in the body to work too fast or too slowly.

In postpartum thyroiditis, inflammation destroys thyroid cells. This causes the thyroid gland to release already-formed thyroid hormones into the bloodstream. After this, there is too much thyroid hormone in the blood, known as hyperthyroidism.

Over time, postpartum thyroiditis can lead to an underactive thyroid, or hypothyroidism, in which the thyroid gland does not make enough thyroid hormones.

According to the American Thyroid Association, postpartum thyroiditis affects roughly 5–10% of females in the United States.

Postpartum thyroiditis may be due to a similar autoimmune disease that causes Hashimoto’s thyroiditis. Certain antithyroid antibodies are typically present in both conditions.

Although Hashimoto’s thyroiditis and postpartum thyroiditis are two different conditions, they have many similarities, and it can be difficult to tell them apart.

At first, the inflammation of the thyroid gland will cause the release of an excess of thyroid hormones into the bloodstream.

People may experience mild, short-term symptoms during this phase. Some people may experience no symptoms at all. If people do experience symptoms, they may include:

People may experience the onset of these symptoms about 1–4 months after childbirth. The symptoms may last 1–3 months, though it may take 12–18 months to regain healthy thyroid function.

If the thyroid gland recovers after this time, postpartum thyroiditis will resolve, and people will not experience any further symptoms.

The condition may continue if damage to the thyroid gland occurs, which can cause a lack of thyroid hormones. This can cause symptoms such as:

Around one-third of people will experience both hyperthyroidism and hypothyroidism, while one-third may only experience one or the other.

People may experience symptoms of hypothyroidism about 4–8 months after giving birth. Symptoms may last 9–12 months.

Although the exact cause of postpartum thyroiditis is not clear, it is an autoimmune disease that may have links with the presence of certain antithyroid antibodies.

Thyroid peroxidase (TPO) is a type of enzyme in the thyroid gland that helps produce thyroid hormones. People with positive TPO antibodies during early pregnancy have a 30–52% risk of developing postpartum thyroiditis.

During pregnancy, levels of TPO antibodies typically decrease. If people still have the TPO antibodies during the third trimester, they have an 80% risk of postpartum thyroiditis.

Risk factors for developing postpartum thyroiditis after childbirth include people with:

  • autoimmune disorders such as type 1 diabetes or juvenile-onset diabetes
  • positive antithyroid antibodies, with higher levels increasing the risk
  • a history of thyroid conditions or postpartum thyroiditis
  • a family history of thyroid conditions

Without treatment, hyperthyroidism may lead to complications such as:

Without treatment, hypothyroidism may cause complications such as:

A doctor can diagnose postpartum thyroiditis using thyroid function tests, which are blood tests that measure thyroid hormones.

Doctors can use thyroid function tests to determine whether people have an overactive or underactive thyroid. Doctors may also carry out a TPO antibody test to check antithyroid antibody levels in the blood.

Thyroid stimulating hormone level

Thyroid function tests will check the level of thyroid stimulating hormone (TSH) in the blood.

The pituitary gland produces TSH. TSH helps to regulate the production of thyroid hormones in the thyroid gland, which are essential for the healthy functioning of multiple systems in the body.

Abnormal changes in a person’s TSH level can be an early warning sign of thyroid issues.

People with postpartum thyroiditis may have lower levels of TSH during the hyperthyroidism stage of postpartum thyroiditis. During the hypothyroidism stage, people may have higher levels of TSH than is typical.

Learn about the TSH level test here.

Treatment for postpartum thyroiditis depends on whether people have hyperthyroidism or hypothyroidism and the severity of symptoms.

Treatment for hyperthyroidism may include beta-blockers, which help to reduce inflammation and symptoms such as heart palpitations. As the hyperthyroidism stage of postpartum thyroiditis is typically short term, a doctor may be able to reduce the person’s dosage as symptoms ease.

If people develop hypothyroidism, they may need thyroid hormone replacement medications. If people have few or no symptoms, their condition may not require treatment and may resolve by itself.

If hypothyroidism continues, people may need to take permanent thyroid hormone medications prescribed by a doctor.

Treatment while nursing

A 2020 article on thyroid disorders after pregnancy recommends that people continue to breastfeed for 6–12 months, including those taking medication for a thyroid condition.

According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDKD), only a small amount of beta-blocker and thyroid hormone medication can reach a child through breast milk, which makes it safe.

A doctor may limit the dosage of medications to ensure it is safe to breastfeed or chestfeed. People can talk with a healthcare professional about breastfeeding or chestfeeding while taking medications to treat postpartum thyroiditis.

The thyroid gland requires certain levels of iodine to produce thyroid hormones. The NIDDKD recommends that people get more iodine during pregnancy and while nursing.

Sources of iodine include:

During the hyperthyroidism stage of postpartum thyroiditis, people may need to limit or avoid iodine intake. Consuming large quantities of iodine may worsen hyperthyroidism. It is important to note that iodine can occur in cough syrups and multivitamins.

People with postpartum thyroiditis can talk with a healthcare professional about foods or supplements that are safe for them to consume and any they need to avoid.

In most cases, postpartum thyroiditis will resolve 12–18 months after symptoms first appear.

However, in some cases, the condition may lead to permanent hypothyroidism. People will need to continue to manage the condition with treatment, possibly including thyroid hormone replacement. Around 20% of people who have hypothyroidism from postpartum thyroiditis may have a permanently underactive thyroid.

Postpartum thyroiditis can also reoccur in other pregnancies. The risk of this is around 20%.

There is currently no clear evidence to suggest that people can help prevent postpartum thyroiditis.

Some research suggests that supplementation with selenium may be a safe and effective way of reducing antithyroid antibodies to help prevent postpartum thyroiditis. However, researchers need to conduct further studies to confirm this.

There are currently no recommended screening practices for checking thyroid function during the postpartum period in people with no symptoms of a thyroid disorder.

People may find the following resources helpful for support with postpartum thyroiditis:

Postpartum thyroiditis can occur after childbirth due to inflammation of the thyroid gland.

People with positive antithyroid antibodies, type 1 diabetes, or a history of thyroid problems may be at higher risk of developing the condition.

Initially, postpartum thyroiditis can cause hyperthyroidism. People may then develop hypothyroidism.

In most cases, the condition will resolve in the 12–18 months following childbirth. However, some people may have permanent hypothyroidism and may need thyroid hormone replacement therapy.