Natural history of patients with hyperprolactinaemia.

One hundred and nineteen women with sustained hyperprolactinaemia were followed for a mean duration of 5.5 years. Where pregnancy was desired, treatment with bromocriptine (+/- clomiphene) was effective in 86% of subjects. Following cessation of bromocriptine therapy one third of subjects whose initial serum prolactin (PRL) level was less than 4 times normal had a 'spontaneous' resolution of their hyperprolactinaemia and resumed cyclical menstrual activity and fertility. Subjects with higher PRL levels or those not treated with bromocriptine, did not show this beneficial effect. Pituitary or hypothalamic tumours were identified in 11% of subjects at the time of presentation and developed in a further 15.1% during follow-up. Most of these tumours were small, occurred more commonly when the PRL level was greater than 4 times normal, and were less likely to develop when treatment with bromocriptine had been administered. Bromocriptine therapy can thus be justified in hyperprolactinaemic subjects to reduce troublesome galactorrhoea, achieve pregnancy, improve the chance of a 'spontaneous' return of menstruation and fertility, control or reduce tumour growth where a pituitary tumour has been identified, and reduce the risk of tumour development in patients with normal plain X-rays of the pituitary fossa at the time of presentation.