Figure 2. Flow chart of GnRH agonist prolonged regimen in Group 1.

One depot of 3.75 mg Triptorelin was injected from 1st to 3rd days of the menstrual cycle, in which ovarian stimulation with 75–300 IU Gns would start 32–38 days later along with confirmation of pituitary downregulation. COH procedure was adjusted according to patients’ ovarian response. One dose of hCG was given when at least two follicles reached 18 mm in mean diameter, and then oocytes were retrieved 34–36 h later. After that, embryo transfer was performed 2–5 days later. Luteal phase support was sustained from the day of oocyte retrieval. (COH, controlled ovarian hyperstimulation; E₂, estradiol; Gns, gonadotropins; hCG, human chorionic gonadotrophin; LH, luteinizing hormone; P, progesterone).