Effects of prolactin and bromocriptine on the luteal phase in infertile women

Infertile women with regular periods but with shortened luteal phases were found to have higher mean levels of serum prolactin and lower serum progesterone levels in the midluteal phase than women with apparently normal ovarian function (P less than 0.001). Serum estrogens and gonadotropins did not differ from the reference group but the ratio FSH/LH was reduced in the midluteal phase (P less than 0.05). LHRH-loading test in the midfollicular phase also resulted in a lower ratio of FSH/LH (P less than 0.05). Thirty-six infertile women with short luteal phases were treated with bromocriptine in a double-blind fashion. The drug moderately reduced the length of the cycle (P less than 0.01). The hyperthermia of the luteal phase was measured planimetrically. Both the total area and the area per day of the luteal phase were significantly increased during the cycles of active treatment (P less than 0.02 and 0.05, respectively). Prolactin was depressed by the drug. After cessation of therapy a very significant rebound elevation of prolactin for at least 2 wk was noted. Bromocriptine therapy further reduced FSH levels at midcycle. Estrogens were elevated during the midluteal phase whereas progesterone was not affected by the treatment. Seven conceptions occurred during the study, six of which during placebo treatment. The conception cycles were characterized by significantly higher levels of progesterone and estrogens during the luteal phase as opposed to the infertile cycles. Four of the pregnancies terminated in spontaneous abortion. The endocrine data of these conception cycles did not differ from those of the successful ones.