Postpartum depression – is your thyroid to blame?

During pregnancy, your immune system is naturally suppressed so that it doesn’t attack the developing foetus. After you give birth, your immune system becomes heightened once again. Although relatively rare, what can happen is that this ‘immune rebound’ can cause postpartum thyroiditis.

What is postpartum thyroiditis?

Postpartum thyroiditis is an autoimmune disease which can occur during the first twelve months after birth. It may represent a thyroid problem that was silent before pregnancy, but those with Type 1 diabetes or a history of thyroid dysfunction are most at risk.

Many symptoms of postpartum thyroiditis can be mistaken for postnatal depression, anxiety, and the stress and exhaustion of having a newborn, so the diagnosis of this condition can be easily missed. Some women with postpartum thyroiditis also report milk supply problems, so if you’re having issues with your supply, it could also be worth ruling out this condition.

What are the symptoms of postpartum thyroiditis?

Postpartum thyroiditis may present as hypothyroid (underactive thyroid) alone, hyperthyroid (overactive thyroid) alone, or a hyperthyroid phase followed by a hypothyroid phase.

Hyperthyroid symptoms may go unnoticed, and usually take place within the first six months. Symptoms can include:

  • Unexplained weight loss
  • Feeling anxious
  • Rapid heartbeat or palpitations
  • Increased sensitivity to heat
  • Excessive hair loss
  • Tremor
  • Irritability
  • Insomnia


Hypothyroid symptoms are usually more obvious, and commonly take place between 4 to 8 months. These symptoms can include:

  • Fatigue
  • Constipation
  • Weight gain
  • Dry skin
  • Aversion to the cold
  • Muscle pain
  • Depression

Getting a diagnosis

See your GP as soon as possible if you experience any of these symptoms. They will take a blood sample to test the levels of thyroid hormones in your blood. The results are usually clear whether it is postpartum thyroiditis.

How is it treated?

Treatment depends on whether you experience hyperthyroid symptoms or hypothyroid symptoms, and also the severity of your condition. For some women, that means that your doctor will monitor you but not prescribe any medications. For more severe symptoms of the hyperthyroid phase, your doctor may prescribe beta-blockers to reduce the symptoms. Equally for those with severe symptoms of the hypothyroid phase, you may be prescribed thyroid replacement therapy.

How long will this condition last?

Most mothers will regain normal thyroid function within 12-18 months after the start of symptoms. A percentage of women don’t recover from the hypothryroid phase, and go on to develop hypothyroidism. For these women, some struggle to make a full milk supply, but if properly treated, many report that they have no supply issues.

If you are breastfeeding, ensure that you let your doctor know before taking prescribed medications. For accurate and up-to-date information about the use of thyroid medications and breastfeeding, contact the Medicines Information Centres in your state (see the Australian Breastfeeding Association’s list of phone numbers here).

Australian Breastfeeding Association


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