The success rate of assisted reproductive technology (ART) has dramatically increased due to the improvements in embryo culture, laboratory conditions, and optimization of different ovarian stimulation protocols. Recent data shows that if hCG is not administered for oocyte maturation, severe OHSS is very rare. However, with gonadotropin releasing hormone (GnRH) agonist cycles, hCG is required. Previous studies have revealed that a smaller dose of hCG used for ovulation trigger versus the standard dose can have the same effect on the induction of final oocyte maturation and can possibly reduce the risk of OHSS . However, the minimal dose required of hCG to maintain maximal success rates of IVF is not known as it has not been adequately studied in randomized controlled trials. Interestingly, our previous randomized controlled study revealed that concomitant administration of FSH and hCG (10,000 IU), a more physiological process, improved developmental oocyte competence. In that study, there was no OHSS in the group that received the FSH co-trigger. A subsequent study performed a randomized trial to determine if FSH co-trigger reduced the incidence of OHSS and found that, it may prevent OHSS. Additionally, our own clinical experience (unpublished data) reveals that administering 1,500 IU hCG plus 450 IU FSH co-trigger is enough to promote adequate oocyte maturation while not increasing the risk of developing OHSS in high risk patients. Given these findings, we propose a further modification of ovulation trigger with decreased exposure to hCG. Our objective is to determine if concomitant administration of FSH with a decreased dose of hCG versus a standard dose of hCG alone for ovulation will promote improved oocyte maturation and quality, while decreasing the risk of OHSS. The selected FSH dose of 450 IU is thought to parallel the physiologic FSH surge observed in a natural cycle. We have chosen 1,500 IU as the designated low dose of hCG based on previous studies showing that even hCG doses as low as 2,000 IU allows oocytes to undergo maturation as well as our own clinical experience that has demonstrated adequate oocyte maturity and fertilization in patients chosen to receive 1,500 IU of hCG, due to the risk of OHSS.