This chapter compares the role of human menopausal gonadotrophin (hMG), follicle-stimulating harmone (FSH) agonist/antagonist and recombinant/urinary human chorionic gonadotrophin (hCG)/luteinizing hormone (LH)/gonadotrophin-releasing hormone agonist (GnRHa) in triggering ovulation. With the use of GnRHa, hCG was necessary to induce final follicular maturation and triggering of ovulation. Accordingly, in the 1980s, the use of gonadotrophins, GnRHa, and hCG became a standard successful protocol for ovulation induction in assisted conception cycles. The GnRH antagonists emerged as an alternative to GnRHa in preventing premature LH surges. Recombinant FSH (recombinant-human FSH), which is free of LH activity, is used in many cases of controlled ovarian hyperstimulation (COH) after downregulation with long protocol. The conclusions of the meta-analyses are that there is no advantage for either recombinant FSH or urinary FSH concerning the clinical pregnancy rate, miscarriage rate, or ovarian hyperstimulation syndrome (OHSS) rate.