RESUMO
UNLABELLED: All forms of thyroid disease are more common in women. The reason for this gender predilection has not been entirely elucidated but may relate to the closely intertwined relationship between thyroid function and the female reproductive axis. Thyroid dysfunction influences both menstrual function and fertility, likely through changes in sex hormone levels, gonadotropin release, and possibly ovarian function. Similarly, alterations in reproductive physiology can modulate thyroid function. In such settings as pregnancy, when sex hormone levels fluctuate markedly, variations in thyroid function occur frequently. For the clinician, understanding when such alterations require intervention is critical. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians LEARNING OBJECTIVES: After completion of this article, the reader will be able to describe the abnormalities of the female reproductive axis associated with both hypo- and hyperthyroidism, to summarize how female sex hormones affect thyroid function, and to explain the effects of pregnancy on thyroid conditions.