Occurence of Permanent Hypothyroidism in Patients with Postpartum Thyroiditis

Postpartum thyroiditis is often a syndrome of transient thyroid dysfunction, but can develop to permanent hypothyroidism in some patients. The incidence of postpartum thyroiditis is variably reported, ranging from 1. 1% to 16. 7%, with an incidence ranging between 11% to 63% for permanent hypothyroidism. This study was conducted to assess the prevalence of permanent hypothyroidism after postpartum thyroiditis in Ahwaz.

All cases of postpartum thyroiditis referred to the endocrinology clinic between 1999 March and 2007 March were followed for 2 to 10 years. Levothyroxin was administered for 6 to 24 months after diagnosis, and then discontinued to evaluate the patients. Based on laboratory hormonal tests, patients were divided into 3 groups: 1) Normal thyroid function test, 2) Sub clinical hypothyroidism, and 3) Clinical hypothyroidism.

Fifty-eight women, were followed 6 months after discontining levothyroxin, twenty five (43. 1%) of group 1, 13 (22. 4%) of group 2, and 20 (34. 5%) in group 3. The average T4 level was significantly higher in group 1 compared to groups 2 and 3 (p =. 003). Permanent hypothyroidism was more frequent in patients who initially (during postpartum thyroiditis) had TSH levels >10 mg/dL. Occurrence of permanent hypothyroidism was less frequent in patients who were initially hyperthyroid. (p =. 006)

It is concluded that a high percentage of patients with postpartum thyroiditis proceed to permanent thyroid failure. The timely recognition of mild to severe cases of postpartum thyroiditis is important for the improvement of life for mothers and infants.