Occurrence of ovarian follicular dominance during stimulation for IVM impacts usable blastocyst yield

OBJECTIVE To evaluate the influence of ovarian follicular dominance on the outcome of oocyte in-vitro maturation. METHODS This retrospective cohort study included 21 patients with polycystic ovaries or polycystic ovary syndrome (Rotterdam criteria, 2004) subjected to 24 invitro maturation (IVM) cycles between October 2015 and January 2017. Patients undergoing IVM received minimal gonadotropin stimulation starting on day 2 or 3 of the cycle; ovum pick-up typically occurred on days 6 to 8. No hCG-trigger shot was given. Following 30h of IVM, mature oocytes were inseminated by ICSI and the resulting embryos cultured up to the blastocyst stage. RESULTS Ovarian follicular dominance was observed in nine of the 24 IVM cycles. Oocyte IVM yielded an overall maturation rate of 69.3±23.8%, and no difference was observed when the groups with or without a dominant follicle were assessed independently. The rates of fertilization and usable blastocysts per fertilized oocyte, mature oocyte (Metaphase II) or cumulus-oocyte-complex were nearly three times higher (28.7±22.5%) in the group without ovarian follicular dominance. No differences were found in the clinical pregnancy rates attained by the individuals with or without a dominant follicle after 21 vitrified-warmed blastocyst transfer cycles. CONCLUSION Occurrence of ovarian follicular dominance during hormonal stimulation for in-vitro maturation negatively impacted embryological outcomes. Strategies devised to limit the appearance of ovarian follicular dominance must be further explored.