Hyperprolactinemia is a disorder in which your pituitary gland produces excessive amounts of the hormone prolactin. Prolactin is a hormone that stimulates milk production in women. Prolactin normally circulates in the blood in small amounts in women who are not pregnant, and in large amounts during pregnancy and right after birth. Hyperprolactinemia can cause irregular or no ovulation, resulting in infertility. Women who have this disorder often have irregular periods, and may also experience galactorrhea—milk production when not pregnant. One of the most common causes of hyperprolactinemia is a benign tumor growing on the pituitary gland—the gland that produces prolactin. The pituitary gland is located in the base of the brain near the vision center. Other causes of excess prolactin production may be an underactive thyroid (hypothyroidism), or certain medications you may be taking. In addition 5% of unselected, asymptomatic infertile women show hyperprolactinemia. In hyperprolactenemic patients fertility may be promoted with long-term use of dopaminergic drugs. Bromocriptine treatment normalizes serum prolactin levels in 80% of patients with idiopathic hyperprolactinemia or microprolactinoma with a preg. In order to induce fertility it is important to maintain the effective PRL lowering dose for 10–12 months since it takes time to reestablish ovulatory cycles and half of the pregnancies occur after the first six months of therapy. Cabergoline effectively treats hyperprolactinemia, micro and macroadenomas with a low incidence of side effects and offers an effective therapy for patients who are resistant or intolerant to bromocriptine.
