Book excerpt: It is an established fact that thyroid hormones play an important role in the metabolism of the body. Pregnancy is a state of significant hormonal as well as metabolic changes, and thyroid hormones have a significant impact on maternal metabolism and fetal development during pregnancy. The fetus relies on maternal thyroid hormone for the development of the CNS, especially in the early stages of gestation, and uncorrected maternal hypothyroidism in this period can leave the child with permanent life-long neurological deficits. From the maternal point of view, a thyroid dysfunction encountered during pregnancy may continue even after delivery as postpartum thyroiditis. Hence, any thyroid dysfunction, be it hypo- or hyperthyroidism, can have serious deleterious consequences if not detected promptly and managed properly. The established guidelines and newer trends for the treatment of thyroid dysfunction are discussed in this update. Thyroid hypofunction has also been known to affect the fertility of women in reproductive age group. With the increasing incidence of infertility and advent of methods to treat them, the early detection and adequate treatment of thyroid hypofunction becomes an unavoidable part of assisted reproductive techniques, in the present day scenario. Even subclinical thyroid disorders can affect the reproductive capacity of non-pregnant women and impact the fetomaternal wellbeing in those who conceive. However, not all cases of subclinical hypothyroidism warrant pharmacological treatment. The guidelines for treatment of subclinical hypothyroidism in the pregnant and non-pregnant states are discussed in detail in this clinical update. An important aspect of reproductive health is family planning, and one of the commonly used means to achieve it is hormonal contraceptives. The interaction of thyroid hormones with hormonal contraceptives and the means of testing thyroid dysfunction in an individual taking hormonal contraceptives have been elucidated in this update.