Postpartum thyroiditis.

Postpartum thyroiditis (PPT) is a syndrome of transient thyroid dysfunction occurring in the first postpartum year. A thyrotoxic phase may be brief and unnoticed before a more long-lasting hypothyroid phase occurs. The incidence is variably reported, ranging from 1.9% to 16.7%, perhaps reflecting racial or geographical differences in the distribution of genetic or environmental risk factors such as the titre of thyroid antibodies and the dietary intake of iodine. The syndrome is an autoimmune disorder, strongly associated with the presence of thyroid microsomal antibody in serum. The thyrotoxic phase may be distinguished from Graves' disease by the finding of low, rather than high, uptake of radioactive iodine or technetium in the thyroid. Screening may be valuable in women with other autoimmune disorders such as Type 1 diabetes mellitus. Treatment should be tailored to the symptoms. Significant thyrotoxic problems should be managed with beta-blocking agents, but severe hypothyroid symptoms should be treated with the short-term replacement thyroxine. A small proportion of affected women will remain permanently hypothyroid. There is also a significant risk of recurrent disease after a subsequent pregnancy.