The clinical therapeutic window for luteinizing hormone in controlled ovarian stimulation.

OBJECTIVE: To discuss the clinical therapeutic window for LH during the follicular phase.
DESIGN: Review of selected papers that were retrieved through a Medline search and a review of clinical trials, the results of which are in the process of publication. PATIENT(S): Women undergoing infertility treatment. INTERVENTION(S): Recombinant human LH (r-hLH) was administered SC as a supplement to FSH during controlled ovarian hyperstimulation. MAIN OUTCOME MEASURE(S): Follicular development, E2 production, and endometrial thickness. RESULT(S): Optimal follicular maturation is the result of both FSH and LH stimulation. In patients with hypogonadotropic hypogonadism, 75 IU of r-hLH and 150 IU of FSH per day resulted in more follicles and provided sufficient E2 for optimal endometrial proliferation. Additional r-hLH (>250 IU/day), in patients with either hypogonadotropic hypogonadism or polycystic ovary disease, may precipitate a series of deleterious physiological actions leading to atresia of developing follicles. Adding r-hLH to FSH in women treated with GnRH agonist showed no benefits in terms of number of mature oocytes, fertilization, and cleavage. However, those who experience profound pituitary desensitization may benefit from adding LH to the stimulation protocol. No obvious clinical criteria have been established to define this group of patients. CONCLUSION(S): A "threshold" and "ceiling" level for LH (therapeutic window) is proposed, below which E2 production is not adequate and above which LH may be detrimental to follicular development.