About the PhD thesis

The most common cause of hyperthyroidism among women of fertile age is the autoimmune Graves’ disease (GD), which is associated with the presence of thyroid-stimulating hormone-receptor antibodies (TRAb) in the blood. In pregnancy, uncontrolled GD can pose a risk to the mother and child. Transient gestational hyperthyroidism is another common cause of hyperthyroidism in pregnancy, and the distinction of this condition from GD is done by measurement of TRAb using an immunoassay. However, immunoassay measurements do not distinguish whether the TRAb are neutral, stimulatory, or blocking, as such distinction requires measurement using a bioassay. The distinction from GD is crucial as gestational hyperthyroidism is a self-limiting phenomenon which, contrary to GD, does not require antithyroid treatment.

There is a close correlation between iodine intake and the occurrence of thyroid disease within a population, and Paper I of the thesis was the first to evaluate how the mandatory iodine fortification program in Denmark changed the occurrence of hyperthyroidism in pregnancy.

Paper II and III of the thesis explored the utility of pregnancy- and method-specific cut-offs for immunoassay measurements of TRAb and bioassay measurements of stimulating TRAb to distinguish between GD and transient gestational hyperthyroidism in a regional cohort.

Paper IV of the thesis described the establishment of a nationwide multicenter study with continued prospective inclusion of pregnant women with GD and women treated with antithyroid drugs in pregnancy, irrespective of the cause of hyperthyroidism.

The findings of the PhD thesis contribute with important knowledge on the occurrence, diagnostics, monitoring, and treatment of hyperthyroidism in pregnancy.