Prolactinoma was diagnosed in 190 women of the same age range, among whom 88 were treated with transsphenoidal microadenectomy and 102 with bromocriptine. The purpose of this study was to compare the two groups according to classification of the adenomas by size and invasiveness, pregnancy rates, prolactin levels after pregnancy, sella turcica changes after pregnancy, and serum prolactin levels and radiologic changes in patients who were operated on but did not become pregnant or did not desire pregnancy. In the group with operation, 91% of patients who had microadenoma and 88% of those with diffuse adenoma conceived, but none who had invasive tumors did so. In the bromocriptine-treated group, among patients with no visible microadenoma or with microadenoma seen radiologically 56% conceived; among those with diffuse adenoma 66% conceived; no patients with invasive adenoma were in this group. In the group with operation, 21% had higher serum prolactin levels and amenorrhea after pregnancy, compared with 19% in the medical treatment group and 19% in the group with operation who did not conceive. Of all patients studied, radiologic changes in the pituitary fossa were seen in only one patient undergoing operation.