Search

Pituitary adenomas are common. The impact of pituitary tumors on fertility are mainly caused by oversecretion and/or undersecretion of pituitary hormones or compression of pituitary stalk and normal pituitary tissue by the tumor. Diagnosing and managing pituitary tumors during pregnancy involve many challenges, including the effect of hormone excess or deficiency on pregnancy outcome, changes in the pituitary or pituitary-related hormones, changes in tumor size, and the impact of various treatments of pituitary tumors on maternal and fetal outcomes. This article discusses the diagnosis and treatment of patients with prolactinomas, acromegaly, Cushing disease, and other pituitary tumors during pregnancy.

Pregnancy may occur in the setting of endocrine diseases or be the first time these diseases manifest clinically. Management of pregnancy in these circumstances is challenging and requires a high degree of vigilance on the part of the treating physicians. The best outcome is achieved by a multidisciplinary approach consisting of endocrinology, obstetrics, anesthesiology, and endocrine surgery.

A number of changes in renal and endocrine physiology occur during pregnancy that alter hormone levels and affect a number of disease processes. Increased glomerular filtration causes an increase in hormone and substrate clearance. Increased placental steroid production causes an increase in hormone-binding globulin production, insulin resistance, and prolactinoma growth. Production of peptide hormones may cause changes in normal physiology and alter dynamic hormone testing. Placental vasopressinase increases vasopressin clearance. A number of diseases of hormone overproduction and underproduction affect pregnancy outcome and must be treated promptly by therapeutic modalities that also may affect the fetus.

Clinically nonfunctioning adenomas (CNFAs) range from being completely asymptomatic, and therefore detected at autopsy or as incidental findings on head MRI or CT scans performed for other reasons, to causing significant hypothalamic/pituitary dysfunction and visual field compromise because of their large size. Patients with incidental adenomas should be screened for hypersecretion and hyposecretion. In the absence of hypersecretion, hypopituitarism, or visual field defects, patients may be followed by periodic screening by MRI for enlargement. Symptomatic patients with CNFAs are generally treated by transsphenoidal resection. Postoperative MRI scans are done at 3 to 4 months after surgery to assess for completeness of resection and then repeated yearly for 3 to 5 years and subsequently less frequently to assess for regrowth. The regrowth rate may be substantially reduced with the use of dopamine agonists and radiotherapy.

Hyperprolactinemia and Cushing's syndrome may interfere with fertility and need to be controlled to allow conception. Cushing's syndrome, acromegaly, and hyperthyroidism secondary to thyroid-stimulating hormone (TSH) hypersecretion may increase maternal morbidity and fetal morbidity and mortality. Removal of an adrenocorticotropin hormone-secreting tumor during pregnancy is warranted to reduce fetal loss, and medical control of hyperthyroidism is indicated. Pregnancy also may cause an increase in prolactin-secreting tumors, especially macroadenomas. In patients with hypopituitarism, thyroid hormone doses should be increased empirically because TSH levels cannot be used. Usually no increase in glucocorticoid dose is needed except to cover the stress of labor and delivery. Lymphocytic hypophysitis may occur with mass effects or hypopituitarism. Appropriate evaluation and hormone replacement are indicated in the acute and chronic forms of Sheehan's syndrome.

Prolactinomas are a common cause of reproductive/sexual dysfunction. Once other causes of hyperprolactinemia have been excluded with a careful history and physical examination, routine chemistries, and an assay for TSH, MR imaging, or CT will delineate the size and extent of the tumor. Medical therapy is the initial treatment of choice. When infertility is the primary indication for treatment, bromocriptine use has an extensive safety record and is preferred. For other indications, cabergoline seems to be more efficacious and better tolerated. Transsphenoidal surgery remains an option, especially for patients with microadenomas, when medical therapy is ineffective.

Prolactinomas are a common cause of reproductive and sexual dysfunction. Once other causes of hyperprolactinemia have been excluded with a careful history, physical examination, routine chemistries, and a TSH, MR imaging or computerized tomography will delineate the size and extent of the tumor. Medical therapy is the initial treatment of choice. When infertility is the primary indication for treatment, bromocriptine use has an extensive safety experience and is preferred. For other indications, however, cabergoline appears to be more efficacious and better tolerated. Transsphenoidal surgery remains an option, especially for patients with microadenomas, when medical therapy is ineffective.

Despite great advances in our understanding of pituitary hormone regulation, the pathogenesis of pituitary tumors remains unknown. There is evidence for and against the hypothesis that growth hormone-, prolactin-, and ACTH-secreting tumors arise as the result of hypothalamic dysregulation. For each of these types of tumor, 80 to 90 per cent appear to arise de novo within the pituitary. Although possible, it is not yet proved that the remaining 10 to 20 per cent arise as a result of underlying hypothalamic dysregulation.