Hyperthyroidism happens when your thyroid gland becomes inflamed and too much thyroid hormone is released into your body. Hyperthyroidism occurs after giving birth in about 5% of pregnancies.

tired mother with postpartum hyperthyroidism holding her babyShare on Pinterest
FatCamera/Getty Images

Postpartum hyperthyroidism is when you have too much thyroid hormone in your body after giving birth.

This condition affects about 5% of people who have given birth and can cause symptoms like a racing heartbeat, anxiety, and weight loss.

For most people, hyperthyroidism in the postpartum period is temporary and resolves within the first year after having a baby.

Let’s take a closer look at postpartum hyperthyroidism, including symptoms, what causes it, diagnosis and treatment, and what the outlook is for people who experience it.

Experiencing hyperthyroidism after delivery is usually part of a condition called postpartum thyroiditis. This is when your thyroid gland becomes inflamed after you have a baby.

The thyroid gland is a butterfly-shaped gland on the lower front part of your neck. It produces thyroid hormones which help regulate your body’s metabolism and ensure that your body’s organs work properly.

People who have postpartum thyroiditis will usually start by experiencing hyperthyroidism (too much thyroid hormone) and then hypothyroidism (too little thyroid hormone).

According to the American Thyroid Association, the phase where you have too much thyroid hormone usually begins within the first 4 months after giving birth and may last 1 to 3 months.

The phase where you have too little thyroid hormone usually starts about 4–8 months after having a baby and can linger for 9–12 months.

Symptoms of postpartum hyperthyroidism vary from one person to another, and it can be easy to confuse these symptoms with the fatigue and anxiety many people experience after having a baby.

Common symptoms of postpartum hyperthyroidism include:

According to the American Thyroid Association, the most common cause of postpartum hyperthyroidism in people without known thyroid disorders is postpartum thyroiditis, an autoimmune condition that causes the thyroid gland to become inflamed.

Postpartum thyroiditis is thought to be similar to an autoimmune condition called Hashimoto’s thyroiditis. Both conditions are linked to increased amounts of anti-thyroid antibodies, such as anti-thyroid peroxidase and anti-thyroglobulin.

Postpartum hyperthyroidism may also occur if you already have a thyroid condition, such as Graves’ disease. Graves’ disease can cause hyperthyroidism and has a high chance of relapsing after you’ve given birth.

Postpartum hyperthyroidism can happen to anyone after they have had a baby, but some people are more likely to experience it than others.

Risk factors for postpartum hyperthyroidism include:

In most cases, postpartum hyperthyroidism goes away on its own and doesn’t require treatment.

If you develop symptoms like heart palpitations or body tremors, you may be prescribed a beta-blocker to help regulate your heartbeat.

If your bout of hyperthyroidism turns into hypothyroidism, you may need to go on an oral medication called levothyroxine.

Among people who have postpartum thyroiditis (the most common cause of hyperthyroidism after birth), an estimated 32% will only experience hyperthyroidism, while 25% of people will experience hyperthyroidism and then hypothyroidism.

In most cases, these conditions will resolve on their own within 12–18 months and you will not experience an ongoing thyroid condition.

Both hyperthyroidism and hypothyroidism can affect your milk supply if you are a breastfeeding parent. If this happens, you can manage it with breastfeeding-safe thyroid medications. Just reach out to your doctor for more information.

If a healthcare professional suspects that you may have postpartum hyperthyroidism, they will perform blood tests to measure your levels of:

  • TSH (thyroid stimulating hormone)
  • T3 and T4 (thyroid hormones)
  • TRAb (thyrotropin receptor antibodies)

Your doctor may also order a radioactive iodine uptake test, where you swallow a capsule of radioactive iodine and the amount of iodine your thyroid absorbs is measured. This test is not safe if you are breastfeeding and may require you to stop breastfeeding for a few days.

Hyperthyroidism postpartum is not preventable. At the same time, if you have any known risk factors, addressing symptoms of hyperthyroidism right away with your healthcare team can make the condition more manageable.

Will I get postpartum hyperthyroidism again?

Having had postpartum hyperthyroidism in one pregnancy increases your risk from developing it in another pregnancy. About 20% of people will find that the condition happens in another pregnancy.

Can hyperthyroidism postpartum affect my baby?

Babies born to parents who have hyperthyroidism in pregnancy or after giving birth are almost always born healthy. Your newborn will be screened for any thyroid conditions as part of routine infant screening.

Is postpartum hyperthyroidism permanent?

Most thyroid issues resolve within a year of giving birth. However, it’s estimated that 30% of people will continue to experience hypothyroidism a year after giving birth, and some will develop lasting hypothyroidism.

Postpartum hyperthyroidism is a condition that affects a small portion of people after giving birth. The condition is often followed by a period of hypothyroidism and can be managed with medication.

If you have symptoms of hyperthyroidism after having a baby — including a racing heartbeat, weight loss, and fatigue — reach out to your OB-GYN, midwife, or primary care doctor for support.