Postpartum Thyroiditis

Cause

• Autoimmune-mediated thyroid injury that occurs in the postpartum period

• Higher risk in:

  • Previous postpartum thyroiditis

  • Positive thyroid peroxidase (TPO) antibodies

  • Type 1 diabetes mellitus (autoimmune predisposition)

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Disease Course

• Typically begins 1–3 months postpartum, although may occur up to 6 months

• Phases

  • Hyperthyroid Phase

    • Often mild and short-lived (1–2 months)

    • Can present with palpitations, anxiety, weight loss, heat intolerance

  • Hypothyroid Phase

    • May last 4–6 months, presenting with fatigue, weight gain, cold intolerance

    • Some women only experience one phase (isolated hyperthyroidism or hypothyroidism)

  • Resolution

    • Usually returns to euthyroid state within 12–18 months postpartum

    • ~20% may develop permanent hypothyroidism

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Clinical Presentation

• Hyperthyroid Symptoms

  • Anxiety, palpitations, irritability, tremor, sweating, weight loss

• Hypothyroid Symptoms

  • Fatigue, weight gain, depression, cold intolerance, constipation, dry skin

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Management

• Monitoring

  • Check TSH and free T4 at diagnosis, then every 4–6 weeks early on to track progression through phases

  • After resolution or treatment cessation, recheck TSH in ~6 weeks

  • Long-term annual TSH recommended due to risk of permanent hypothyroidism

• Hyperthyroid Phase

  • Typically mild and self-limiting

  • Symptomatic relief with beta-blockers (e.g. propranolol 10–40 mg BD) if palpitations or significant adrenergic symptoms

  • No routine role for antithyroid drugs (e.g. carbimazole) unless hyperthyroidism persists >1 year or if Graves’ disease is suspected

  • If clinical or biochemical features suggest Graves’ (ophthalmopathy, very high T3/T4, positive TSH receptor antibodies), obtain radionuclide imaging or TSI testing

• Hypothyroid Phase

  • Treat with levothyroxine if symptomatic or TSH >10 mU/L

  • Typical starting dose: 50–100 mcg daily, adjusted based on TSH/free T4

  • Continue for 6–12 months, then attempt cessation and recheck TSH after 6 weeks to determine if thyroid function has normalised

  • If TSH remains elevated, long-term levothyroxine may be required

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Notes & Follow-Up

• Women who have experienced postpartum thyroiditis have an increased risk of future thyroid dysfunction, both in subsequent pregnancies and later in life

• Educate on recognising symptoms early in postpartum periods

• Emphasise the importance of regular follow-up, especially TSH monitoring in future pregnancies or annually if initial postpartum thyroiditis resolves

• Suspect postpartum thyroiditis in any new mother with thyroid-related symptoms within 12 months of delivery

• Early phase hyperthyroidism often does not require thionamides, but symptomatic control with beta-blockers is helpful

• Address hypothyroidism promptly if TSH is significantly elevated or clinical symptoms are problematic

• Monitor TSH periodically even after apparent resolution to catch the 20% who develop permanent hypothyroidism