The use of luteinising hormone releasing hormone agonists for ovarian stimulation in assisted reproductive technology.

Although the use of luteinising hormone releasing hormone (LHRH) agonists and human menopausal gonadotrophin (hMG) for ovarian stimulation in assisted reproductive technology has gained wide-spread popularity, a number of major issues regarding their use remain unresolved. In this paper, we examine some of these issues in the light of the results of our own studies. We have found that although the use of LHRH agonists may be advantageous for some patients, its routine use for all patients produces no significant medical advantage compared with conventional stimulation regimens. In a number of prospective randomised studies, we have found that the long protocol of LHRH agonist administration is superior to the short and ultrashort protocols and the administration of glucocorticoids to patients at high risk of developing ovarian hyperstimulation syndrome does not reduce the incidence of this complication. Finally, we have found that when the long protocol of LHRH agonist administration is used, precise timing of human chorionic gonadotrophin administration (hCG) is not important. There are no significant differences in oocyte recovery, fertilisation and cleavage rates, or in pregnancy rates when the results of standard timing of hCG administration are compared with delayed administration. It would, therefore, appear that the major advantage of the routine use of LHRH agonists is for practical, rather than medical reasons.