Thyroiditis, Hypothyroidism, and Hyperthyroidism After Pregnancy

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It's common for women to feel tired, experience mood swings, and have a variety of other symptoms in the months after childbirth. But for some women, symptoms can become troublesome and may point to a thyroid problem, known as postpartum thyroiditis.

Postpartum thyroiditis is an inflammation of the thyroid that initially occurs in the first year after childbirth, miscarriage, or induced abortion. It's considered a variation of autoimmune thyroiditis, also known as Hashimoto's thyroiditis.

Who Is at Risk?

If you have been pregnant, you can develop postpartum thyroiditis. The condition is fairly common, as it's estimated that approximately 7 percent of women develop it.

The risks of getting postpartum thyroiditis are higher if you have the following conditions and/or thyroid markers:

  • Up to 25 percent of women with type 1 diabetes develop postpartum thyroiditis.
  • Up to 50 percent of women with elevated anti-peroxidase (anti-TPO) antibodies develop postpartum thyroiditis.

Typical Course

The most common course for postpartum thyroiditis is mild hypothyroidism starting from two to six months after your baby is born. The hypothyroidism then resolves as your thyroid normalizes.

The next most common presentation is mild hyperthyroidism, which begins one to four months after delivery, after which your thyroid normalizes.

A third course is characterized by mild hyperthyroidism that then shifts into a period of mild hypothyroidism for several weeks to several months, followed by normalization of thyroid function. 

While some cases of after postpartum thyroiditis resolve over time, there is a strong risk that the woman will continue to have a thyroid condition.

It's estimated that as many as half of people with postpartum thyroiditis will, within four to eight years, develop persistent hypothyroidism, a goiter (an enlarged thyroid gland), or both.

Symptoms

There are a number of symptoms of postpartum thyroiditis that may appear during both the hyperthyroid and hypothyroid phases of the condition. These include:

  • Decreased milk volume in breastfeeding women
  • Hair loss
  • Fatigue
  • Goiter that is painless
  • Depression, anxiety, and moodiness

Symptoms during the hyperthyroid phase of postpartum thyroiditis are usually milder versions of general hyperthyroidism symptoms. These symptoms may include anxiety, muscle weakness, irritability, heart palpitations, fast heartbeat, tremor, weight loss, and diarrhea.

Likewise, the symptoms during the hypothyroid phase of postpartum thyroiditis are milder versions of general hypothyroidism symptoms. They may include sluggishness, dry skin, difficulty losing weight (or weight gain), constipation, low body temperature, and puffiness in the eyes, face, and hands.

Diagnosis

Your doctor will typically run several blood tests to diagnose postpartum thyroiditis. In the hyperthyroid phase, your blood tests typically show a low thyroid-stimulating hormone (TSH), and high-normal or elevated thyroxine (T4) and triiodothyronine (T3).

In the hypothyroid phase, your TSH will be elevated, and T4 and T3 will be low or low-normal. Thyroid peroxidase (TPO) antibody levels are likely to be elevated in the majority of women with postpartum thyroiditis, especially during the hypothyroid phase.

In some cases of postpartum thyroiditis, an ultrasound is performed and will show enlargement of your thyroid gland.

It's important to note that along with postpartum thyroiditis, autoimmune Graves' disease (which causes hyperthyroidism) may occur after your baby is born. While postpartum thyroiditis is a far more common cause of hyperthyroidism, your doctor will want to ensure he does not miss a diagnosis of Graves' disease.

Some distinguishing factors are that in Graves' disease, a woman has more severe symptoms, more thyroid enlargement, and may have eye-related symptoms (called Graves' ophthalmopathy). 

In some cases, a radioiodine uptake test is done to differentiate postpartum thyroiditis from Graves' disease. (Note, however, this test is not performed if you are breastfeeding.)

Treatment

In most cases, you will not need treatment for postpartum thyroiditis during either the hyperthyroid or the hypothyroid phases. Symptoms are usually mild, and the condition frequently resolves on its own, within several months to as much as a year after your baby is born.

However, if your symptoms of hyperthyroidism are uncomfortable, your doctor may prescribe a beta-blocker, such as propranolol or atenolol. (Breastfeeding is not suggested while taking beta blockers, however.) Antithyroid drugs are not used for hyperthyroid symptoms in postpartum thyroiditis.

If hypothyroidism during postpartum thyroiditis causes significant symptoms, experts recommend thyroid hormone replacement treatment. Typically, after six to twelve months on the medication, your doctor will recommend stopping it, so you can be tested again to see if your postpartum thyroiditis has resolved.

A Word From Verywell

After you have had postpartum thyroiditis, you have a substantially increased risk of developing it again in future pregnancies. When planning a pregnancy, or when you are pregnant, make sure that your doctors are aware of any past thyroid issues. 

In addition, postpartum thyroiditis increases your risk of developing hypothyroidism or a goiter later on in life. This is why it's important to have your thyroid function evaluated annually.  

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Article Sources
  • Alexander EK, et. al.2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum. Thyroid. 2017 Mar;27(3):315-389.

  • Burman, Kenneth. Postpartum Thyroiditis. UpToDate.