Endocrine Abstracts

Thyroid hormones play crucial roles in foetal growth and neurodevelopment which are dependent on adequate supply of maternal thyroid hormones from early gestation onwards. During pregnancy there are important physiological changes resulting in altered reference ranges and complicating the interpretation of thyroid function tests. Thyroid dysfunction is common in pregnancy and the prevention of adverse obstetric and foetal outcomes relies upon careful monitoring and treatment before and during pregnancy.

Overt and subclinical hypothyroidism are usually managed through increased doses of levothyroxine replacement, although there is ongoing debate regarding the optimal target ranges as well as the need for universal screening. Further controversies surround the management of isolated hypothyroxinaemia and TPO antibody positivity before and during pregnancy and particularly in the setting of infertility.

Hyperthyroidism in women of childbearing age is usually due to Graves’ disease. In the early stages of pregnancy the differential diagnosis from transient gestational thyrotoxicosis may be difficult. Uncontrolled thyrotoxicosis in pregnancy is associated with poor outcomes and optimisation of thyroid function prior to conception as well as careful management of treatment during pregnancy are crucial for mother and foetus.

Thyroid nodules are common in the general population and may occur in women of childbearing age. Their management is similar to that outside the setting of pregnancy. When thyroid cancer is diagnosed during pregnancy, often a conservative approach is adopted for low risk tumours. In patients who are on suppressive treatment with levothyroxine following treatment of thyroid cancer, careful monitoring of thyroid function is required.

This lecture will give an overview of the diagnosis and management of thyroid diseases before, during and after pregnancy with reference to the most up to date national and international guidelines.