Short-term luteinizing hormone-releasing hormone agonist treatment: prospective trial of a novel ovarian stimulation regimen for in vitro fertilization.

Over a period of 4 months, 262 infertile couples participated in a prospective pseudorandom trial of a novel short-term luteinizing hormone-releasing hormone/human menopausal gonadotropin (LH-RH/hMG) treatment; the short-Buserelin-gonadotropin (Hoechst, Hounslow, United Kingdom) regimen. Patients treated with the short-Buserelin-gonadotropin regimen had a significantly higher likelihood of achieving pregnancy than patients treated with the standard clomiphene citrate (CC)/hMG regimen (respectively, 35.5% and 18% per treatment cycle). A significantly higher number of eggs were collected after short-Buserelin-gonadotropin treatment than CC/hMG, but the proportion of patients having a given number of embryos replaced was similar in the two groups. The short-Buserelin-gonadotropin-treated patients were distinguished from the CC/hMG-treated group by significantly lower levels of LH in the late follicular phase and a lower plasma level of estradiol. A detrimental relationship between elevated endogenous LH secretion and failure of implantation has been established. The nature of the short-Buserelin-gonadotropin regimen provokes high levels of endogenous gonadotropin secretion in the early follicular phase and induces a suppression of gonadotropin secretion in the late follicular phase. This may be the physiologic basis of the greater implantation rate after short-Buserelin-gonadotropin treatment than is seen with conventional CC/hMG treatment.