In the last two decades, there have been major advances in our understanding of thyroid physiology during pregnancy and the role of thyroid hormones in fetal development. Increasing evidence during the period has highlighted that even mild maternal thyroid dysfunction can have adverse effects on fetal neuropsychological development and other pregnancy outcomes. The importance of trimester-specific reference ranges for thyroid function tests in pregnancy has emerged. Randomised controlled trials are beginning to provide evidence base for the management of various thyroid disorders in pregnancy.

However, there remain many unanswered questions in relation to thyroid and pregnancy. For example, how does maternal thyroid hormone transport to the fetus and influence fetal brain development at the molecular level? There is lack of consensus on several clinical management issues. For example, should all pregnant women be screened for thyroid dysfunction, what are the cut-off levels for maternal subclinical hypothyroidism and maternal hypothyroxinemia in pregnancy, and when to start treatment for these conditions? Also, despite all national and international programs to optimise dietary iodine intake in the populations, iodine deficiency during pregnancy continues to be a major preventable cause of mental retardation in many countries. Furthermore, the recent studies have raised concerns about potential adverse effects of environmental thyroid hormone disruptors on pregnancy outcomes.

The main focus of this special issue will be pregnancy-related thyroid disorders. We invite authors to submit original research (clinical or basic science) as well as review articles that will enhance our understanding of thyroid physiology and pathology in relation to pregnancy. We are also interested in articles exploring adverse effects and management of thyroid dysfunction in pregnancy. Potential topics include, but are not limited to:

• Physiological, environmental, and genetic factors affecting thyroid function in pregnancy
• Thyroid and fetal brain development
• Iodine deficiency and pregnancy
• Congenital hypothyroidism
• Transient hypothyroxinemia of prematurity
• Thyroid in relation to infertility and its treatment
• Thyroid autoimmunity and pregnancy
• Thyroid hormone insufficiency and pregnancy
• Hyperthyroidism and pregnancy
• Postpartum thyroid dysfunction
• Goitre, thyroid lump, and thyroid cancer in pregnancy
• Thyroid surgery in pregnancy
• Environmental thyroid hormone disruptors and pregnancy

Before submission authors should carefully read over the journal's Author Guidelines, which are located at http://www.hindawi.com/journals/jtr/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/ according to the following timetable: