Transient hyperprolactinemia: a correctable cause of idiopathic female infertility.

Frequent measurements of prolactin throughout the menstrual cycle were obtained in 48 women with regular menses and longstanding idiopathic infertility. Forty-five of the 48 patients (94%) had a small but significant transitory preovulatory elevation in their serum prolactin levels (hPRL). These transitory elevations in hPRL to 27-70 ng/ml lasted only one to three days and coincided with the preovulatory estradiol peak. When this transient hyperprolactinemia was suppressed by treatment with an appropriate, titrated dose of bromergocriptine, 18 patients (40%) conceived within one to three months. Evidently, this transitory, relatively mild hyperprolactinemia was not sufficient to interfere with follicular maturation, ovulation, or corpus luteum function, but it may impair fertilization and/or implantation.