RESUMO
STUDY QUESTION: Are there factors predicting the number of total and mature oocytes retrieved after controlled ovarian hyperstimulation (COH) utilizing a gonadotropin-releasing hormone (GnRH) antagonist protocol and a GnRH agonist (GnRHa) to induce oocyte maturation? SUMMARY ANSWER: Peak estradiol (E2) level, post-trigger LH and progesterone and the magnitude of LH rise are independent predictors of the total number of oocytes and mature oocytes retrieved. WHAT IS KNOWN ALREADY: Despite multiple follicular development in high responders, oocyte retrieval after a GnRHa trigger in a small subset of patients fails to obtain a substantial number of total oocytes or mature oocytes. STUDY DESIGN, SIZE AND DURATION: A retrospective chart review of all autologous and oocyte donation cycles utilizing a GnRHa antagonist protocol where GnRHa was used for the induction of oocyte maturation between 1 April 2003 and 31 December 2011. PARTICIPANTS/MATERIALS, SETTING AND METHODS: A total of 508 autologous and donor IVF/ICSI cycles utilizing a GnRH antagonist protocol for COH and GnRHa for the induction of oocyte maturation at a university-based tertiary fertility center. MAIN RESULTS AND THE ROLE OF CHANCE: Peak E2 on the day of trigger (r = 0.19, P < 0.001), post-trigger LH (r = 0.12, P = 0.009) and progesterone (r = 0.47, P < 001) and LH rise (r = 0.18, P < 0.001) all positively correlated with the number of total and mature oocytes retrieved. The true incidence of empty follicle syndrome was 1.4% (7/508). There was no post-trigger LH or progesterone cut-off value for the prediction of oocyte yield. However, all cases of empty follicle syndrome occurred in patients with post-trigger LH <15 IU/l and P ≤ 3.5 ng/ml. The findings of this study may also be due to chance since it was a retrospective study and not prospectively designed. LIMITATION, REASONS FOR CAUTION: This is a retrospective chart review and therefore subject to bias. Serum hormone measurements were performed between 8 and 12 h after GnRHa trigger rather than a standardized time period following trigger administration. Therefore, peak levels of LH may have been missed due to the short ascending limb of LH rise lasting approximately 4 h after GnRHa trigger. WIDER IMPLICATIONS OF THE FINDINGS: The results of this study can be generalized to high responders utilizing a GnRH antagonist protocol for COH and a GnRHa for the induction of oocyte maturation. The use of alternative stimulation regimens or medications will limit the ability to generalize the results of this study to other populations. STUDY FUNDING/COMPETING INTEREST(S): This study was not funded, and there are no conflicts of interest. TRIAL REGISTRATION NUMBER: n/a.
