Serum prolactin levels and the value of bromocriptine in the treatment of anovulatory infertility.

Basal serum levels of prolactin were measured in 37 infertile anovulatory patients who had failed to conceive on therapy with clomiphene citrate. Twenty of these patients, 16 of whom had galactorrhoea, had elevated basal serum prolactin values which were suppressed to normal or subnormal values during therapy with bromocriptine, the most commonly effective dose being 2.5 mg twice daily. Ovulation, as assessed by urinary oestrogen and pregnanediol measurements, was induced in 17 of these patients with pregnancy in 14. Ovarian responses short of defined criteria for ovulation were induced initially in eight patients, but these progressed to full ovulatory responses in five patients, either on the same or increased doses of bromocriptine. In all the patients who ovaulated, the prolactin levels had been reduced below the mean value for normal women (10.6 ng-ml). The three patients who failed to ovulate all had values higher than this at a dose of bromocriptine reaching 5.0 mg thrice daily. There seemed to be no value in increasing the dose of bromocriptine once ovulation had been achieved. Of the 17 patients with normal basal prolactin values, only one had an unequivocal response to bromocriptine with ovulation and conception, even though the prolactin values in the majority were suppressed to below normal.