Monitoring of Thyroid Malfunction and Therapies in Pregnancy and the Postpartum Period: A Systematic Updated Critical Review of the Literature.

PURPOSE: From the very beginning of pregnancy, the maternal thyroid has to adapt to increased thyroid hormone secretion of up to 50%. This is paralleled by changes in thyroid-stimulating hormone secretion and by the thyroid-topic action of human chorionic gonadotropin. Thus, hypothyroidism and hyperthyroidism may occur. Many women exhibit preexisting thyroid diseases. This review tries to add the most recently published approaches to diagnosing thyroid malfunction in pregnancy to existing guidelines. METHODS: Different literature-based approaches to diagnosing thyroid malfunction during pregnancy and the postpartum period were applied. To diagnose thyroid malfunction in pregnancy, trimester-specific reference ranges for thyroid-stimulating hormone and T4 are used. RESULTS: Definitions of thyroid malfunction are given. Treatment schedules for various thyroid diseases were reviewed and, on the basis of recent findings, were revised where necessary. For a daily clinical workup, this outline not only suggests diagnostic and therapeutic steps but also refers to frequent pitfalls and misinterpretations of laboratory data. CONCLUSIONS: Although the body of knowledge is increasing rapidly, the authors believe that this review is able to present new ideas concerning diagnostic and therapeutic tools for thyroid malfunction in pregnancy and the postpartum period. Nevertheless, there seems to remain room for individual approaches based on the personal experience of physicians who deal with these issues regularly.