Clinical practice guideline for hypotalamic-pituitary disturbances in pregnancy and the postpartum period.

During pregnancy, the body undergoes a major adaptation process as a result of the interaction between mother, placenta and fetus. Major anatomical and histological changes are produced in the pituitary, with an increase of up to 40% in the size of the gland. There are wide variations in the function of the hypothalamus-pituitary-thyroid axis that effect iodine balance, the overall activity of the gland, as well as transport of thyroid hormones in plasma and peripheral metabolism of thyroid hormones. The incidence of goiter and thyroid nodules increases throughout pregnancy. The management of differentiated thyroid carcinoma should be individually tailored according to tumoral type and pregnancy stage. Given the effects of hypothyroidism on fetal development, both the diagnosis and appropriate therapeutic management of thyroid hypofunction are essential. The most important modification to the hypothalamus-pituitary-adrenal axis during pregnancy is the rise in serum cortisol levels due to an increase in cortisol-binding proteins. Although Cushing's syndrome during pregnancy is infrequent, both diagnosis and treatment of this disorder are especially difficult. Adrenal insufficiency during pregnancy does not substantially differ from that occurring outside pregnancy. However, postpartum pituitary necrosis (Sheehan's syndrome) is a well-known complication that occurs after delivery and, together with lymphocytic hypophysitis, constitutes the most frequent cause of adrenal insufficiency. The management of prolactinoma during pregnancy requires suppression of dopaminergic agonists and their reintroduction if there is tumoral growth. Notable among the neuropituitary disorders that can occur throughout pregnancy is diabetes insipidus, which occurs as a consequence of increased vasopressinase activity.