This is another class of medications which, when administered, prevent premature ovulation. They are used for a short period of the last phase of stimulation. Potential adverse reactions: immunological system disorders: (uncommon) cases of hypersensitivity reactions including pseudo-allergic/anaphylactic reactions. Nervous system disorders: (uncommon) headache. Gastrointestinal disorders: (uncommon) nausea. Reproductive system and breast disorders: (common) mild to moderate ovarian hyperstimulation syndrome can occur, which is an intrinsic risk of the stimulation procedure, (uncommon) severe ovarian hyperstimulation syndrome. Administration site conditions (common): local reactions at the injection site (erythema, swelling and pruritus) have been reported; typically, they had transient and mild character.