Preventing, identifying and managing thyroid deficiency in prenatal practice

Despite the lack of consensus among groups issuing recent guidelines, it is possible to identify options that are available for prenatal practitioners. Examples include the following: iodine supplements to protect against hypothyroidism; adjusting l-thyroxine dosage upward in women with previously diagnosed hypothyroidism to account for increased pregnancy needs; and screening for undetected thyroid deficiency via targeted questions and/or thyroid-stimulating hormone testing. Decision-making about thyroid status requires access to reliable, trimester-specific normative data for both thyroid-stimulating hormone and free thyroxine, as well as an understanding of the impact of human chorionic gonadotropin on thyroid function, especially during the first trimester. Continuity of care is enhanced by systematic follow-up postpartum, including attention to postpartum thyroid dysfunction that often occurs among women with raised antibody levels.