Postpartum thyroiditis (PPT) is a type of autoimmune thyroiditis. It usually develops in the postpartum period and the entire course of the disease lasts for 6-12 months. Typical cases go through three clinical phases, namely the thyrotoxic phase, the hypothyroid phase and the recovery phase. Atypical cases may present with only the thyrotoxic phase or the hypothyroid phase. Laboratory tests are positive for TPOAb or/and TgAb. TT4 and FT4 are elevated and then decreased. The symptoms of the thyrotoxic phase of postpartum thyroiditis are often mild and anti-thyroid drug (ATD) therapy is not recommended. Treatment with beta-blockers, such as propranolol, may be used for symptomatic women, taking the smallest possible dose and requiring several months of medication. L-T4 therapy may be given to those with severe symptoms in the hypothyroid phase of postpartum thyroiditis. Frequency of follow-up: every 4-8 weeks. After 6-12 months of treatment, a gradual dose reduction may be attempted. Within a year 10-20% of women whose nail function has returned to normal develop permanent hypothyroidism . Over a period of 5-8 years, approximately 50% of women develop permanent hypothyroidism. Risk factors for the development of permanent hypothyroidism include the degree of hypothyroidism, TPOAb titers, maternal age and history of miscarriage. Therefore, patients with PPT should have their TSH checked annually for 8 years after the onset of the disease to detect and treat hypothyroidism as early as possible.