Investigation and management of symptomatic hyperprolactinaemia

Fifteen patients with infertility and hyperprolactinaemia have been investigated using tests of prolactin and LH secretion, and treated by prolactin suppression. In addition, 4 patients with hyperprolactinaemia not desiring fertility were also investigated. Of the total group, 16 had galactorrhoea and 15 had amenorrhoea. Pituitary tumours were present in 6 patients and 4 had pituitary microadenomas. Prolactin levels measured by both radioimmunoassay and radioreceptor assay were elevated before treatment and fell during therapy with bromoergocryptine (7.5 mg daily). Tests of prolactin release with TRH and chlorpromazine before treatment did not distinguish patients with functional hyperprolactinaemia from those with pituitary tumours. Basal plasma gonadotrophin concentrations were not elevated despite subnormal urinary oestrogen levels. The serum LH response to LRH was normal during hyperprolactinaemia, but LH release in response to oestrogen provocation was impaired in 14 of 17 patients. During prolactin suppression, mean oestrogen excretion rose significantly and the oestrogen provocation test became normal in all except 2 patients. Pregnancy occurred in all of the 15 patients desiring fertility. Abortion has occurred in 4 patients, all of whom are currently pregnant again. Nine pregnancies have reached term, with no complications from pituitary expansion. It appears that during hyperprolactinaemia there are defects in both positive and negative feedback of oestrogen on LH secretion, and that prolactin suppression in such patients is highly effective in restoring fertility.