Background: A great concern exists in using corifollitropin alfa to induce ovarian stimulation in high responders due to the riskof OHSS.In this study, we utilized corifollitropin alfa in patients with the potential of being high responders, in addition to the GnRH analogue triptorelin, as final trigger to induce the oocyte maturation. An intensive luteal support was administered to allow the transfer in the same cycle. Patients and methods:Between January 2013 and September 2014, 35 patients were stimulated with corifollitropin alfa and underwent in vitro fertilization or intracytoplasmic sperm injection procedures. All women had levels of antimullerian hormone>3 ng/ml and antral follicle count >10 and <20. The patients with polycystic ovarian syndrome were excluded from the study. Results:The mean number of oocytes collected was 13.95 ± 6.04, the mean number of oocytes inseminated was 5.11 ± 1.66, the mean number of embryos obtained and transferred was 3.13 ±1.61 and 2.11 ± 0.92, respectively. All patients received a fresh embryo transfer,and the luteal phase was intensively supported by triptorelin and progesterone.A part of oocytes (2.47 ± 4.28) and blastocysts (0.39 ± 0.75) was vitrified.The clinical pregnancy was achieved in 15 patients and the ongoing pregnancy in11 women. Cumulative ongoing pregnancy rate, including the pregnancies achieved after thawing of eggs or embryos, was 39.47%. No OHSS were observed. Conclusions:Corifollitropin alfa plus triptorelin trigger elicits a safe ovarian stimulation in the potential high responderpatients. first day after insemination.Luteal phase was supportedby triptorelin 0.1 mg, one injection every other day from the embryo transfer, for a total of five injections. Additionally, 600 mg/day of micronized progesterone (Progeffik 200 mg, 3 cps/die) was started from the day of oocyte retrieval. A quantitative pregnancy test, done by dosing serum β-hCG, was performed 12 days after ovulation triggering with triptorelin and it was repeated 2 days later. In the presence of pregnancy, a transvaginal ultrasound was performed 28-32 days after the embryo transfer and repeated as required. Clinical pregnancy was confirmed if a fetal heartbeat was observed by transvaginal ultrasound. ResultsCharacteristics of ovarian stimulation and IVF/ICSI parameters are described in Table 1. Despite the patients included in this study had a high follicular response (14 women had over 15 oocytes retrieved), the ovarian stimulation protocol allowed to obtain a good fertilization rate and top-and good-quality embryos.Our results show that, in this group ofthe potential high responder patients, 15 clinical pregnancies and 11 ongoing pregnancies were achieved per fresh cycle ( Table 2). The cumulative ongoing pregnancy rate reached 39.47%, including 4 ongoing pregnancies which were obtained after the transfer of frozen-thawed oocyte (in one patient) and blastocysts (in three patients). Some of the pregnancies have already delivered the birth of a healthy baby. All patients reported good comp...