What is postpartum thyroiditis?

Postpartum thyroiditis is a temporary, inflammatory condition that occurs in less than 1 in 10 pregnancies. It is more common in women who have thyroid autoantibodies. This condition normally shows up in the first 12 months after birth. It does not require treating with antithyroid drugs.

What are the symptoms?

It usually starts off with symptoms of hyperthyroidism (weight loss, anxiety, heat intolerance, tremor) and women may have a painless lump in their neck. This is followed by symptoms of hypothyroidism (feeling tired, low mood, cold).

Is treatment needed?

• Do not prescribe antithyroid drugs in the thyrotoxic phase of postpartum thyroiditis.
• If symptoms, consider prescribing levothyroxine. Most women can stop taking these after 6 to 12 months. Around 1 in 3 women will need to take levothyroxine long-term.

Testing

• Do not test for this unless there are risk factors e.g. thyroid autoantibodies, or symptoms of thyroid disease.
• Check thyroid function every 6-8 weeks, and assess symptoms, in women with symptoms of postpartum thyroiditis but normal thyroid levels.

If thyroid levels later become out of range, consider testing TRAb antibodies (raised in Graves’ disease, unlikely to be raised in postpartum thyroiditis) and isotope scanning (diffuse uptake in Graves’ disease, no uptake in postpartum thyroiditis) to distinguish between postpartum thyroiditis or Graves’ disease.

Follow-up

• Recommend annual TSH testing in women who have had postpartum thyroiditis as they have an increased risk of developing permanent hypothyroidism.
• Counsel women that they are at higher risk of developing postpartum thyroiditis in subsequent pregnancies and that they should have their thyroid function checked as soon as possible in subsequent pregnancies.

Read the RCOG Green-top guideline on the Management of Thyroid Disorders in Pregnancy