Postpartum thyroiditis: risk factors, differential diagnosis, clinical features

Abstract

Postpartum thyroiditis (PT), one of the commonest causes of disturbed thyroid function (TF), is believed to occur in 5% of the women. The present study involving 57 patients with PT was designed to study risk factors and clinical features of this pathology as well as approaches to its diagnosis. Two control groups comprised female carriers of anti- thyroid peroxidase antibodies (TPO-AB) without PT and women having symptoms of Graves disease (GD) in the postpartum period, respectively. Patients with PT were shown to have significantly elevated TPO-AB levels during pregnancy compared with controls. Postpartum GD manifested itself later than PT, it was associated with a significantly higher freeT4 level and a greater thyroid volume. In twenty of the 57 women with PT, it was manifest in the thyrotoxic phase and in the remaining 37 in the hyperthyroid state. The TSH level in the first half of pregnancy was significantly higher in the women that eventually developed a monophasic hypothyroid variant of PT. In the same group, the TPO-AB level at the time of PT diagnosis was significantly higher than in the biphasic variant of PT. Forty (70%) of the 57 women with PT recovered to an euthyroid state by the end of the study whereas in 17 (30%) hypothyroidism persisted. The biphasic variant of PT was manifest starting from the thyrotoxic phase and more frequently ended in the recovery to the euthyroid state (90%) than the monophasic one, the difference being statistically significant. In contrast, the monophasic hypothyroid variant more frequently resulted in persistent hypothyroidism (40%).