Luteinizing hormone increases estradiol secretion but has no effect on progesterone concentrations in the late follicular phase of in vitro fertilization cycles in women treated with gonadotropin-releasing hormone agonist and follicle-stimulating hormone

Objective: To determine whether the late follicular phase increase in circulating P concentrations during controlled ovarian stimulation with GnRH-a and FSH can be influenced by addition of LH to the stimulating gonadotropin during the final 2 days. Design: Randomization of patients to receive either FSH alone or FSH with LH (hMG) for the final 2 days before hCG, after follicular phase stimulation with purified FSH. Setting: A.C.S. Unit at the Royal Infirmary, Glasgow, U.K. Patient(s): Patients were unselected and were undergoing IVF. Intervention(s): Patients received stimulation with purified FSH (300 IU/d) until a follicle of 15 min was observed; the regimen was then changed to either 225 IU of FSH or 215 IU of hMG. Main Outcome Measure(s): Estradiol and P in the peripheral circulation. Result(s): Significant increases in E-2 concentration were observed, but there were no changes in the circulating progesterone. Conclusion(s): The late follicular phase increase in P is unrelated to any luteinizing process attributable to effects in the circulation or sensitization of follicular cells to LH. (C) 1998 by American Society for Reproductive Medicine.