Serum prolactin levels in normal women and in women with disorders of menstruation.

The mean (+/-SD) serum prolactin (PRL) level of 78 normal premenopausal women was 10-6+/-3-0 ng/ml, and this was significantly different from that of post-menopausal women (8-2+/-4-0 ng/ml) and women taking combined oral contraceptive preparations (12-2+/-4-0 ng/ml). No significant differences were found between follicular and luteal phase PRL levels. Serum PRL levels higher than the ranges given above were found in 31 of 87 patients with secondary amenorrhoea and two of 41 patients with oligomenorrhoea. Nine of the 33 patients with hyperprolactinaemia did not have galactorrhoea. Only two of the patients with hyperprolactinaemia had pituitary tumours evident on skull X-ray films. Serum PRL levels were of value in predicting the likely success in achieving ovulation with clomiphene citrate or CB-154; clomiphene citrate was less likely to be successful in the presence of hyperprolactinaemia, whereas the reverse applied for treatment with CB-154.