In assisted reproductive technology (ART), follicular growth is stimulated with exogenous gonadotropins to obtain multiple mature oocytes for fertilization. In a natural cycle, oocyte maturation and ovulation is triggered by endogenous luteinizing hormone (LH). To prevent a premature surge of LH and subsequent premature ovulation and cancellation of the ART cycle, a gonadotropin releasing hormone (GnRH) agonist is commonly used to inhibit endogenous gonadotropin release leading to premature ovulation or luteinization. After a short-term initial stimulation of the pituitary gland, continuous administration of a GnRH agonist leads to the downregulation of GnRH receptors of the pituitary and thus prevents synthesis and release of follicle-stimulating hormone (FSH) and LH from that organ.