Endocrine Abstracts

Introduction: Postpartum thyroiditis (PPT) occurs during the first postpartum year with a prevalence between 1.1% and 16.7%. It presents either as transient hyperthyroidism, transient hypothyroidism, or transient hyperthyroidism followed by transient hypothyroidism. Anti-thyroid peroxidase antibodies (TPOAb) levels are high in 60-85% of cases, while the less measured anti-thyroglobulin antibodies (TgAb) can also be high. Risk factors for PPT include presence of thyroid antibodies prior to pregnancy and a history of previous PPT. We present a woman who had PPT affecting three consecutive pregnancies.

Case Presentation: A 33-year-old woman presented with heat intolerance, palpitations, and breathlessness three months after delivery. She had a history of PPT occurring after two previous pregnancies. The first episode occurred three months postpartum. She subsequently developed transient hypothyroidism requiring levothyroxine replacement for three months. The second episode also occurred three months postpartum and was followed by transient hypothyroidism three months later. She had no other medical history, not on regular medication and was a non-smoker.

Investigations and management: Initial results revealed mild thyrotoxicosis with exacerbation a month later, while on beta-blocker therapy (Table). Ultrasound scan demonstrated increased vascularity consistent with thyroiditis. TPOAb and thyroid receptor antibodies (TRAb) were negative, but TgAb were positive. She developed worsening hypothyroidism over the second and third month, followed by spontaneous recovery over the fourth and fifth month.

Conclusion: This woman had the classic triphasic pattern during all three episodes of postpartum PPT, with negative test for TPOAb but positive test for TgAb. This case serves as a reminder to check TgAb in patients with TPOAb-negative PPT.