Objective: This study aimed to examine the association between serum estradiol levels and number of metaphase II oocytes harvested after in vitro fertilization cycles used in embryo transfers and the subsequent impact on pregnancy rates.
Methods: This observational analytical retrospective study was carried out in 2010-2018 at the Angeles del Pedregal Hospital. It included 181 cases and looked into the number of metaphase II oocytes to predict pregnancy rates. Statistical analysis was based on the calculation of correlations between variables and logistic regressions.
Results: Estradiol levels increased with the number of oocytes by a median correlation (r=0.482, p=0.000). On the day of trigger, estradiol levels predicted the number of retrieved oocytes with 23% reliability (R2=0.232, p=0.000); a linear trend correlation of r=0.489, p=0.000 was found between estradiol levels on the day of trigger and number of metaphase II oocytes.
Conclusions: Serum estradiol on the day of trigger as a predictor of metaphase II oocytes in antagonist cycles encourages greater oocyte maturity and fertilization, whereas, in isolation, it does not determine the pregnancy achievement.
Keywords: antagonists; estradiol; oocyte retrieval; pregnancy rate; trigger day.