Effect of transitory hyperprolactinemia on in vitro fertilization of human oocytes

To examine the changes in plasma prolactin (PRL) during ovarian hyperstimulation (OH) and the influence of hyperprolactinemia on folliculogenesis, oocyte retrieval and in vitro fertilization (IVF) success rates and the usefulness of the metoclopramide (MCP) test in predicting the onset of hyperprolactinemia.

Forty-nine cycles of OH were induced in 32 infertile women using follicle-stimulating hormone, human menopausal gonadotropin and human chorionic gonadotropin (GI) (n = 36), also in association with gonadotropin-releasing hormone (GII) (n = 13). The MCP test (10 mg, intravenously) was performed on fertile control women (control group, n = 9) and in GI (n = 21) and GII (n = 8) patients.

Plasma PRL and estradiol levels increased during OH, reaching maximum levels on the day preceding oocyte retrieval in GI and GII. Since these two groups exhibited similar PRL curves, they were evaluated as a single group. Patients showing an increase in PRL of > 200% presented a greater number of follicles with a mean diameter > or = 12 mm and more mature oocytes and better IVF success rates than patients with a PRL increase < or = 200%. Oocyte retrieval did not differ between the groups. The MCP test showed hyperresponsiveness in the three groups studied, but no correlation was found between the PRL increase in this test and that during OH.

Plasma PRL and estradiol levels increase during OH, while the MCP test cannot predict the onset of hyperprolactinemia. Transitory hyperprolactinemia seems to be associated with an increase in the numbers of follicles with a mean diameter > or = 12 mm and with more mature oocytes and better IVF success rates.