The influence of the thyroid on pregnancy outcomes

Adequate serum thyroid hormone concentrations in women are crucial for an uncomplicated pregnancy and optimal fetal growth and development. Pregnancy has a profound impact on the thyroid gland and its function. Various changes occur during pregnancy to maintain normal thyroid hormone concentrations. The pregnancy specific alterations and the increased demand for thyroid hormone, causes women with pre-existing mild thyroid dysfunction to be exposed to gestational thyroid disease.
Several pregnancy complications have been associated with thyroid disorders, such as (recurrent) pregnancy loss, pre-eclampsia, intrauterine growth restriction and premature delivery, as well as effects upon fetal neurocognitive development. In this thesis the focus was on recurrent pregnancy loss (RPL), which has a strong association with subclinical thyroid disease, including subclinical hypothyroidism and thyroid auto-immunity. The higher prevalence of subclinical thyroid disease makes it an important public health issue, although the risks of adverse pregnancy outcomes in case of subclinical hypothyroidism and thyroid auto-immunity are lower than in case of overt thyroid disease, such as hypo- and hyperthyroidism.
RPL is a distressing condition for most couples and a significant health problem. It affects the physical and psychological well-being of prospective parents. It is also experienced as a frustrating problem for the physician because in the majority of cases there is no known therapy which increases the chance of a live born baby. As a result, in addition to lifestyle advices and supportive care, the doctor feels he or she cannot offer the couple much.
In this thesis we studied the associations between thyroid disorders and pregnancy outcomes, we developed a diagnostic strategy for recurrent pregnancy loos and determined the efficacy of treatment with levothyroxine.